document_title: Turntablism

question_text: who created the unique combination of cutting and double backing called the quick mix theory

text: Turntablism

text: History[edit]

text: Precursors[edit]

text: The use of the turntable as a musical instrument has its roots dating back to the 1930s, 1940s, and 1950s when musique concrète composers did experiments with audio equipment. Experimental composers (such as John Cage, Halim El-Dabh, and Pierre Schaeffer) used them to sample and create music that was entirely produced by the turntable. Cage's Imaginary Landscape No. 1 (1939) is composed for two variable speed turntables, frequency recordings, muted piano and cymbal. Edgard Varèse experimented with turntables even earlier in 1930, though he never formally produced any works using them. Though this school of thought and practice is not directly linked to the 1970s-2010 definition of turntablism within hip hop and DJ culture, it has had an influence on modern experimental sonic/artists such as Christian Marclay, Janek Schaefer, Otomo Yoshihide, and Philip Jeck. However, turntablism as it is known today did not surface until the development of hip hop in the 1970s.

text: Examples of turntable effects can also be found on popular records produced in the 1960s and 1970s. This was most prominent in Jamaican dub music of the 1960s,[3] among deejays in the Jamaican sound system culture. Dub music introduced the techniques of mixing and scratching vinyl,[4] which Jamaican immigrants introduced to American hip hop culture in the early 1970s.[5] Beyond dub music, Creedence Clearwater Revival's 1968 self-titled debut album features a backspin effect in the song "Walk on the Water."

text: Direct-drive turntables[edit]

text: Turntablism has origins in the invention of direct-drive turntables. Early belt-drive turntables were unsuitable for turntablism, since they had a slow start-up time, and they were prone to wear-and-tear and breakage,[6] as the belt would break from backspinning or scratching.[7] The first direct-drive turntable was invented by Shuichi Obata, an engineer at Matsushita (now Panasonic),[8] based in Osaka, Japan.[6] It eliminated belts, and instead employed a motor to directly drive a platter on which a vinyl record rests.[9] In 1969, Matsushita released it as the SP-10,[9] the first direct-drive turntable on the market,[10] and the first in their influential Technics series of turntables.[9] In 1971, Matsushuta released the Technics SL-1100. Due to its strong motor, durability, and fidelity, it was adopted by early hip hop artists.[9]

text: A forefather of turntablism was DJ Kool Herc, an immigrant from Jamaica to New York City.[10] He introduced turntable techniques from Jamaican dub music,[5] while developing new techniques made possible by the direct-drive turntable technology of the Technics SL-1100, which he used for the first sound system he set up after emigrating to New York.[10] The signature technique he developed was playing two copies of the same record on two turntables in alternation to extend the b-dancers' favorite section,[5] switching back and forth between the two to loop the breaks to a rhythmic beat.[10]

text: The most influential turntable was the Technics SL-1200,[11] which was developed in 1971 by a team led by Shuichi Obata at Matsushita, which then released it onto the market in 1972.[6] It was adopted by New York City hip hop DJs such as Grand Wizard Theodore and Afrika Bambaataa in the 1970s. As they experimented with the SL-1200 decks, they developed scratching techniques when they found that the motor would continue to spin at the correct RPM even if the DJ wiggled the record back and forth on the platter.[11] Since then, turntablism spread widely in hip hop culture, and the SL-1200 remained the most widely used turntable in DJ culture for the next several decades.[9][11]

text: Hip-Hop[edit]

text: Turntablism as a modern art form and musical practice has its roots within African-American inner city Hip-Hop and Hip-Hop culture of the late 1970s. Kool Herc (a Jamaican DJ who immigrated to New York City), Afrika Bambaataa and Grandmaster Flash are widely credited for having cemented the now established role of DJ as hip hop's foremost instrumentalist.[12] Kool Herc's invention of break-beat DJing is generally regarded as the foundational development in hip hop history, as it gave rise to all other elements of the genre. His influence on the concept of "DJ as turntablist" is equally profound.

text: To understand the significance of this achievement, it is important to first define the "break." Briefly, the "break" of a song is a musical fragment only seconds in length, which typically takes the form of an "interlude" in which all or most of the music stops except for the percussion. Kool Herc introduced the break-beat technique as a way of extending the break indefinitely. This is done by buying two of the same record, finding the break on each record, and switching from one to the other using the DJ mixer: e.g., as record A plays, the DJ quickly backtracks to the same break on record B, which will again take the place of A at a specific moment where the audience will not notice that the DJ has switched records. Using that idea, Grandmaster Flash elaborated on Kool Herc's invention of break-beat DJing and came up with the quick-mix theory, in which Flash sectioned off a part of the record like a clock.[13] He described it as being "...like cutting, the backspin, and the double-back." [14]

text: Kool Herc's revolutionary techniques set the course for the development of turntablism as an art form in significant ways. Most important, however, he developed a new form of DJing that did not consist of just playing and mixing records one after the other. The type of DJ that specializes in mixing a set is well respected for his/her own set of unique skills, but playlist mixing is still DJing in the traditional sense. Kool Herc instead originated the idea of creating a sequence for his own purposes, introducing the idea of the DJ as the "feature" of parties, whose performance on any given night would be different than on another night, because the music would be created by the DJ, mixing a bassline from one song with a beat from another song. The DJ would be examined critically by the crowd on both a technical and entertainment level.

text: Grand Wizzard Theodore, an apprentice of Flash, who accidentally isolated the most recognizable technique of turntablism: scratching. He put his hand on a record one day, to silence the music on the turntable while his mother was calling out to him and thus accidentally discovered the sound of scratching by moving the record back and forth under the stylus. Though Theodore discovered scratching, it was Flash who helped push the early concept and showcase it to the public, in his live shows and on recordings. DJ Grand Mixer DXT is also credited with furthering the concept of scratching by practicing the rhythmic scratching of a record on one or more turntables (often two), using different velocities to alter the pitch of the note or sound on the recording (Alberts 2002). DXT appeared (as DST) on Herbie Hancock's hit song "Rockit."[12] These early pioneers cemented the fundamental practice that would later become the emerging turntablist art form. Scratching would during the 1980s become a staple of hip hop music, being used by producers and DJs on records and in live shows. By the end of the 1980s it was very common to hear scratching on a record, generally as part of the chorus of a track or within its production.

text: On stage the DJ would provide the music for the MCs to rhyme and rap to, scratching records during the performance and showcasing his or her skills alongside the verbal skills of the MC. The most well known example of this 'equation' of MCs and DJ is probably Run-D.M.C. who were composed of two MCs and one DJ. The DJ, Jam Master Jay, was an integral part of the group since his turntablism was critical to Run DMC's productions and performances. While Flash and Bambaataa were using the turntable to explore repetition, alter rhythm and create the instrumental stabs and punch phrasing that would come to characterize the sound of hip hop, Grandmaster DST was busy cutting "real" musicians on their own turf. His scratching on Herbie Hancock's 1983 single, "Rockit," makes it perhaps the most influential DJ track of them all – even more than (Grandmaster Flash's) "Wheels of Steel," it established the DJ as the star of the record, even if he wasn't the frontman.  Compared to "Rockit," West Street Mob's "Break Dancin' – Electric Boogie" (1983) was punk negation. As great as "Break Dancin'" was, though, it highlighted the limited tonal range of scratching, which was in danger of becoming a short-lived fad like human beat-boxing until the emergence of Code Money's DJ Brethren from Philadelphia in the mid-1980s.

text: Despite New York's continued pre-eminence in the hip-hop world, scratch DJing was modernized less than 100 miles down the road in Philadelphia, where the climate for the return of the DJ was created by inventing transformer scratching. Developed by DJ Spinbad, DJ Cash Money and DJ Jazzy Jeff, transforming was basically clicking the fader on and off while moving a block of sound (a riff or a short verbal phrase) across the stylus. Expanding the tonal as well as rhythmic possibilities of scratching, the transformer scratch epitomized the chopped-up aesthetic of hip hop culture. Hip hop was starting to become big money and the cult of personality started to take over. Hip hop became very much at the service of the rapper and Cash Money and DJ Jazzy Jeff were accorded maybe one track on an album – for example, DJ Jazzy Jeff's "A Touch of Jazz" (1987) and "Jazzy's in the House" (1988) and Cash Money's "The Music Maker" (1988). Other crucial DJ tracks from this period include Tuff Crew's DJ Too Tuff's "Behold the Detonator"  "Soul Food" (both 1989)," and Gang Starr's "DJ Premier in Deep Concentration" (1990).

text: Decline in role of DJ in hip hop[edit]

text: The appearance of turntablists and the birth of turntablism was prompted by one major factor – the disappearance or downplaying of the role of the DJ in hip-hop groups, on records and in live shows at the turn of the 1990s. This disappearance has been widely documented in books and documentaries (among them Black Noise and Scratch: The Movie), and was linked to the increased use of DAT tapes and other studio techniques that would ultimately push the DJ further away from the original hip-hop equation of the MC as the vocalist and the DJ as the music provider alongside the producer. This push and disappearance of the DJ meant that the practices of the DJ, such as scratching, went back underground and were cultivated and built upon by a generation of people who grew up with hip hop, DJs and scratching. By the mid-90s the disappearance of the DJ in hip hop had created a sub-culture which would come to be known as turntablism and which focused entirely on the DJ utilizing his turntables and a mixer to manipulate sounds and create music. By pushing the practice of DJing away, hip hop created the grounds for this sub-culture to evolve.

text: Coining of terms[edit]

text: The origin of the terms turntablist and turntablism are widely contested and argued about, but over the years some facts have been established by various documentaries (Battlesounds, Doug Pray's Scratch), books (DJ Culture), conferences (Skratchcon 2000) and interviews in online and printed magazines. These facts are that the origins of the words most likely lay with practitioners on the US West Coast, centered on the San Francisco Bay Area. Some claim that DJ Disk, a member of the Invisibl Skratch Piklz, was the first to coin the term, others claim that DJ Babu, a member of the Beat Junkies, was responsible for coining and spreading the term turntablist after inscribing it on his mixtapes and passing them around. Another claim credits DJ Supreme, 1991 World Supremacy Champion and DJ for Lauryn Hill. The truth most likely lies somewhere in between all these facts.

text: In an interview with the Spin Science online resource in 2005, DJ Babu added the following comments about the birth and spread of the term:

text: It was around 95, I was heavily into the whole battling thing, working on the tables constantly, mastering new techniques and scratches...[I] made this mixtape called "Comprehension," and on there was a track called "Turntablism" which featured Melo-D and D-Styles. And this is part of where this whole thing about turntablist came from. This was a time where all these new techniques were coming out, like flares and stuff, and there were probably 20 people or so, in around California between Frisco and LA, who knew about these. So we worked on them, talked about it and kicked about the ideas that these techniques and new ways of scratching gave us.

text: [citation needed]

text: Mid-to late 1990s[edit]

text: By the mid to late 1990s the terms "turntablism" and "turntablist" had become established and accepted to define the practice and practitioner of using turntables and a mixer to create or manipulate sounds and music. This could be done by scratching a record or manipulating the rhythms on the record either by drumming, looping or beat juggling. The decade of the 1990s is also important in shaping the turntablist art form and culture as it saw the emergence of pioneering artists (Mix Master Mike, DJ Q-Bert, DJ Quest, DJ Krush, A-Trak, Ricci Rucker, Mike Boo, Pumpin' Pete, Prime Cuts) and crews (Invisibl Skratch Piklz, Beat Junkies, The Allies, X-Ecutioners), record labels (Asphodel), DJ Battles (DMC) and the evolution of scratching and other turntablism practices such as Beat Juggling which are viewable in the IDA (International DJ Association/ITF) World Finals.

text: Techniques[edit]

text: More sophisticated methods of scratching were developed during that decade, with crews and individual DJs concentrating on the manipulation of the record in time with the manipulation of the cross fader on the mixer to create new rhythms and sonic artefacts with a variety of sounds. The evolution of scratching from a fairly simple sound and simple rhythmic cadences to more complicated sounds and more intricate rhythmical patterns allowed the practitioners to further evolve what could be done with scratching musically. These new ways of scratching were all given names, from flare to crab or orbit, and spread as DJs taught each other, practiced together or just showed off their new techniques to other DJs. Alongside the evolution of scratching, other practices such as drumming (or scratch drumming) and beat juggling were also evolved significantly during the 1990s.

text: Beat juggling was invented by Steve Dee, a member of the X-Men (later renamed X-Ecutioners) crew. Beat juggling essentially involves the manipulation of two identical or different drum patterns on two different turntables via the mixer to create a new pattern. A simple example would be to use two copies of the same drum pattern to evolve the pattern by doubling the snares, syncopating the drum kick, adding rhythm and variation to the existing pattern. From this concept, which Steve Dee showcased in the early 1990s at DJ battles, Beat Juggling evolved throughout the decade to the point where by the end of it, it had become an intricate technique to create entirely new "beats" and rhythms out of existing, pre-recorded ones. These were now not just limited to using drum patterns, but could also consist of other sounds – the ultimate aim being to create a new rhythm out of the pre-recorded existing ones. While beat juggling is not as popular as scratching due to the more demanding rhythmical knowledge it requires, it has proved popular within DJ battles and in certain compositional situations.

text: Studies[edit]

text: One of the earliest academic studies of turntablism (White 1996) argued for its designation as a legitimate electronic musical instrument—a manual analog sampler—and described turntable techniques such as backspinning, cutting, scratching and blending as basic tools for most hip hop DJs. White's study suggests the proficient hip-hop DJ must possess similar kinds of skills as those required by trained musicians, not limited to a sense of timing, hand–eye coordination, technical competence and musical creativity. By the year 2000, turntablism and turntablists had become widely publicized and accepted in the mainstream and within hip hop as valid artists. Through this recognition came further evolution.

text: Evolution[edit]

text: This evolution took many shapes and forms: some continued to concentrate on the foundations of the art form and its original links to hip hop culture, some became producers utilizing the skills they'd learnt as turntablists and incorporating those into their productions, some concentrated more on the DJing aspect of the art form by combining turntablist skills with the trademark skills of club DJs, while others explored alternative routes in utilizing the turntable as an instrument or production tool solely for the purpose of making music – either by using solely the turntable or by incorporating it into the production process alongside tools such as drum machines, samplers, computer software, and so on.  Digital turntablism techniques later was coined into a term called controllerism, which inspired a movement of new digital DJs such as DJ Buddy Holly and Moldover.  DJ Buddy and Moldover went on to create a song called "Controllerism" that pays homage to the sound of digitally emulated turntablism.

text: New DJs, turntablists and crews owe a distinct debt to old-school DJs like Kool DJ Herc, Grand Wizard Theodore, Grandmaster Flash, DJ Jazzy Jeff, Afrika Bambaataa and other DJs of the golden age of hip hop, who originally developed many of the concepts and techniques that evolved into modern turntablism. Within the realm of hip hop, notable modern turntablists are the cinematic[when defined as?] DJ Shadow, who influenced Diplo and RJD2, among others,[citation needed] and the experimental DJ Spooky, whose Optometry albums showed that the turntablist can perfectly fit within a jazz setting.[according to whom?] Mix Master Mike was a founding member of the influential turntablist group Invisibl Skratch Piklz (begun in 1989 as Shadow of the Prophet) and later DJ for the Beastie Boys. Cut Chemist, DJ Nu-Mark, and Kid Koala are also known[by whom?] as virtuosi of the turntables.

text: Techniques[edit]

text: Chopped and screwed[edit]

text: Starting in the 1990s in the Southern United States and burgeoning in the 2000s, a meta-genre of hip hop called "chopped and screwed" became a significant and popular form of turntablism. Often utilizing a greater variety of vinyl emulation software rather than normal turntables, "chopped and screwed" stood out from previous standards of turntablism in its slowing of the pitch and tempo ("screwing") and syncopated beat skipping ("chopping"), among other added effects of sound manipulation.

text: DJ Screw of Texas, innovated the art of chopping and screwing coining the phrase "chopped n screwed," taking original contemporary hit records and replaying them in the "chopped n screwed" art form.  This gained a very large following finally paving the way for small, independent rap labels to turn a decent profit. However, it is thought by many that DJ Michael Price started slowing down vinyl recordings before the era of DJ Screw.

text: This form of turntablism, which is usually applied to prior studio recordings (in the form of custom mixtapes) and is not prominent as a feature of live performances, de-emphasizes the role of the rapper, singer or other vocalist by distorting the vocalist's voice along with the rest of the recording. Arguably, this combination of distortion and audial effects against the original recording grants greater freedom of improvisation to the DJ than did the previous forms of turntablism. Via the ChopNotSlop movement, "Chopped and screwed" has also been applied to other genres of music such as R&B and rock music, thus transcending its roots within the hip-hop genre.[15][16]

text: Transform[edit]

text: A transform is a type of scratch used by turntablists.  It is made from a combination of moving the record on the turntable by hand and repeated movement of the crossfader. The name, which has been associated with DJ Jazzy Jeff,[17] comes from its similarity to the sound made by the robots in the 1980s cartoon, The Transformers.

text: Tear[edit]

text: A tear is a type of scratch used by turntablists. It is made from moving the record on the turntable by hand. The tear is much like a baby scratch in that one does not need the fader to perform it, but unlike a baby scratch, when the DJ pulls the record back he or she pauses his or her hand for a split second in the middle of the stroke. The result is one forward sound and two distinct backward sounds. This scratch can also be performed by doing the opposite and placing the pause on the forward stroke instead. A basic tear is usually performed with the crossfader open the entire time, but it can also be combined with other scratches such as flares for example by doing tears with the record hand and cutting the sound in and out with the fader hand.

text: Orbit[edit]

text: An orbit is a type of scratch used by turntablists.  It is generally any scratch that incorporates both a forward and backward movement, or vice versa, of the record in sequence. The orbit was developed by DJ Disk who incorporated the flare after being shown by DJ Q-Bert.[citation needed] Usually when someone is referring to an orbit, they are most likely talking about flare orbits. For example, A 1 click forward flare and a 1 click backward flare in quick succession (altogether creating 4 very quick distinct sounds) would be a 1 click orbit. A 2 click forward flare and a 2 click backward flare in quick succession (altogether creating 6 very distinct sounds) would be a 2 click orbit, etc. Orbits can be performed once as a single orbit move, or sequenced to produce a cyclical never ending type of orbit sound.

text: Flare[edit]

text: Flare is a type of scratch used by turntablists.  It is made from a combination of moving the record on the turntable by hand and quick movement of the crossfader. The flare was invented by its namesake, DJ Flare in 1987. This scratch technique is much like the "transform" in some ways, only instead of starting with the sound that is cutting up off, one starts with the sound on and concentrate on cutting the sound into pieces by bouncing the fader off the cut out side of the fader slot to make the sound cut out and then back in a split second.

text: Each time the DJ bounces the fader off the side of the fader slot it makes a distinct clicking noise. For this reason, flares are named according to clicks. A simple one click forward flare would be a forward scratch starting with the sound on as the DJ bounces/clicks the fader against the side once extremely quickly in the middle of the forward stroke creating two distinct sounds in one stroke of your record hand and ending with the fader open. In the same manner, 2 clicks, 3 clicks, and even more clicks (if a DJ is fast enough) can be performed to do different types of flares. The discovery and development of the flare scratch was instrumental in elevating this art form to the level of speed and technical scratching that is seen in the 2010s.

text: Chirp[edit]

text: A "chirp" is a type of scratch used by turntablists. It is made with a mix of moving the record and incorporating movement with the crossfade mixer. It was invented by DJ Jazzy Jeff. The scratch is somewhat difficult to perform because it takes a good amount of coordination. The scratch starts out with the cross-fader open. The DJ then moves the record forward while simultaneously closing the previously opened channel ending the first sound. Then, in a reverse fashion, the DJ opens the channel while moving the record backwards creating a more controlled sounding "baby scratch". Done in quick succession it sounds as though a chirp sound is being produced.

text: Stab[edit]

text: A "stab" is quite similar to the Chirp technique but requires the crossfade mixer to be "closed". The stab requires the user to push the record forward and back quickly and moving the crossfade mixer with your thumb pressed against it, which results in minimal sound coming out, producing a sharp "stabbing" noise".

text: Crab[edit]

text: A "crab" is a type of scratch used by turntablists. It was invented by DJ Qbert. It is one of the most difficult scratch techniques to master. The crab is done by pushing the record forward and back while pushing the crossfader mixer open or closed through a quick succession of 4 movements with your fingers. Variations can also include 3 or 2 fingers, and generally it is recommended for beginners to start with 2 fingers and work their way to 4. It is a difficult move to master but also versatile and quite rewarding if done right.

text: Visual turntablism[edit]

text: Visual turntablism is a more recent phenomenon in which "visual turntablists," or "VJs," incorporate pictures, video, and computer generated effects into their live performances utilizing a separate video mixer in combination with their turntablist equipment. It can contain visuals without the audio being necessarily directly associated or synchronized. Since video mixing became incorporated into DJ hardware from Pioneer, and DJ software such as Scratch Live, visual turtablism have moved from being a DJ with a "VJ," to being solely the DJ mixing music videos much the same way as music was mixed before. In 2005 the International Turntablist Federation World final introduced the 'Experimental' category, Australian DJ/VJ 'DJ J-red' took first place, becoming the first Australian to win a World DJ competition championship title as well as becoming a pioneer of the Visual Turntablist movement.

text: Contests[edit]

text: Like many other musical instrumentalists, turntablists compete to see who can develop the fastest, most innovative and most creative approaches to their instrument. The selection of a champion comes from the culmination of battles between turntablists. Battling involves each turntablist performing a routine (A combination of various technical scratches, beat juggles, and other elements, including body tricks) within a limited time period, after which the routine is judged by a panel of experts. The winner is selected based upon score. These organized competitions evolved from actual old school "battles" where DJs challenged each other at parties, and the "judge" was usually the audience, who would indicate their collective will by cheering louder for the DJ they thought performed better. The DMC World DJ Championships has been hosted since 1985. There are separate competitions for solo DJs and DJ teams, the title of World Champion being bestowed on the winners of each. They also maintain a turntablism hall of fame.[18]

text: Role of women[edit]

text: In Western popular music, women musicians have achieved great success in singing and songwriting roles, with top examples being Madonna, Celine Dion and Rihanna. However, there are relatively few women DJs or turntablists. Part of this may stem from a general low percentage of women in audio technology-related jobs. A 2013 Sound on Sound article stated that there are "...few women in record production and sound engineering."[19] Ncube states that "[n]inety-five percent of music producers are male, and although there are female producers achieving great things in music, they are less well-known than their male counterparts."[19]  The vast majority of students in music technology programs are male.

text: In hip hop music, the low percentage of women DJs and turntablists may stem from the overall male domination of the entire hip hop music industry. Most of the top rappers, MCs, DJs, record producers and music executives are men. There are a small number of high-profile women, but they are rare. In 2007 Mark Katz's article "Men, Women, and Turntables: Gender and the DJ Battle," stated that "very few women [do turntablism] battle[s]; the matter has been a topic of conversation among hip-hop DJs for years."[20] In 2010 Rebekah Farrugia states "the male-centricity of EDM culture" contributes to "a marginalisation of women in these [EDM] spaces." [21] While turntablism and broader DJ practices should not be conflated, Katz suggests use or lack of use of the turntable broadly by women across genres and disciplines is impacted upon by what he defines as "male technophilia."[20] Historian Ruth Oldenziel concurs in her writing on engineering with this idea of socialization as a central factor in the lack of engagement with technology. She explains: "an exclusive focus on women's supposed failure to enter the field … is insufficient for understanding how our stereotypical notions have come into being; it tends to put the burden of proof entirely on women and to blame them for their supposedly inadequate socialization, their lack of aspiration, and their want of masculine values. An equally challenging question is why and how boys have come to love things technical, how boys have historically been socialized as technophiles."[22]

text: Lucy Green has focused on gender in relation to musical performers and creators, and specifically on educational frameworks as they relate to both.[23] She suggests that women's alienation from "areas that have a strong technological tendency such as DJ-ing, sound engineering and producing" are "not necessarily about her dislike of these instruments but relates to the interrupting effect of their dominantly masculine delineations."[24] Despite this, women and girls do increasingly engage in turntable and DJ practices, individually[25] and collectively,[26] and "carve out spaces for themselves in EDM and DJ Culture".[21] There are various projects dedicated to the promotion and support of these practices such as Female DJs London.[27] Some artists and collectives go beyond these practices to be more gender inclusive.[28] For example, Discwoman, a New York-based collective and booking agency, describe themselves as "representing and showcasing cis women, trans women and genderqueer talent."[29]


document_title: Corrosion

question_text: why does corrosion usually occur at an anode

question_tokens: why does corrosion usually occur at an anode

root

text: Corrosion

text: Galvanic corrosion[edit]

text: Galvanic corrosion occurs when two different metals have physical or electrical contact with each other and are immersed in a common electrolyte, or when the same metal is exposed to electrolyte with different concentrations. In a galvanic couple, the more active metal (the anode) corrodes at an accelerated rate and the more noble metal (the cathode) corrodes at a slower rate. When immersed separately, each metal corrodes at its own rate. What type of metal(s) to use is readily determined by following the galvanic series. For example, zinc is often used as a sacrificial anode for steel structures. Galvanic corrosion is of major interest to the marine industry and also anywhere water (containing salts) contacts pipes or metal structures.

tag: p

text: Factors such as relative size of anode, types of metal, and operating conditions (temperature, humidity, salinity, etc.) affect galvanic corrosion. The surface area ratio of the anode and cathode directly affects the corrosion rates of the materials. Galvanic corrosion is often prevented by the use of sacrificial anodes.

text: Galvanic series[edit]

text: In any given environment (one standard medium is aerated, room-temperature seawater), one metal will be either more noble or more active than others, based on how strongly its ions are bound to the surface. Two metals in electrical contact share the same electrons, so that the "tug-of-war" at each surface is analogous to competition for free electrons between the two materials. Using the electrolyte as a host for the flow of ions in the same direction, the noble metal will take electrons from the active one. The resulting in mass flow or electric current can be measured to establish a hierarchy of materials in the medium of interest. This hierarchy is called a galvanic series and is useful in predicting and understanding corrosion.

text: Corrosion removal[edit]

text: Often it is possible to chemically remove the products of corrosion. For example, phosphoric acid in the form of naval jelly is often applied to ferrous tools or surfaces to remove rust. Corrosion removal should not be confused with electropolishing, which removes some layers of the underlying metal to make a smooth surface. For example, phosphoric acid may also be used to electropolish copper but it does this by removing copper, not the products of copper corrosion.

text: Resistance to corrosion[edit]

text: Some metals are more intrinsically resistant to corrosion than others (for some examples, see galvanic series). There are various ways of protecting metals from corrosion (oxidation) including painting, hot dip galvanizing, and combinations of these.[2]

text: Intrinsic chemistry[edit]

text: The materials most resistant to corrosion are those for which corrosion is thermodynamically unfavorable. Any corrosion products of gold or platinum tend to decompose spontaneously into pure metal, which is why these elements can be found in metallic form on Earth and have long been valued. More common "base" metals  can only be protected by more temporary means.

text: Some metals have naturally slow reaction kinetics, even though their corrosion is thermodynamically favorable. These include such metals as zinc, magnesium, and cadmium. While corrosion of these metals is continuous and ongoing, it happens at an acceptably slow rate. An extreme example is graphite, which releases large amounts of energy upon oxidation, but has such slow kinetics that it is effectively immune to electrochemical corrosion under normal conditions.

text: Passivation[edit]

text: Passivation refers to the spontaneous formation of an ultrathin film of corrosion products, known as a passive film, on the metal's surface that act as a barrier to further oxidation. The chemical composition and microstructure of a passive film are different from the underlying metal. Typical passive film thickness on aluminium, stainless steels, and alloys is within 10 nanometers. The passive film is different from oxide layers that are formed upon heating and are in the micrometer thickness range – the passive film recovers if removed or damaged whereas the oxide layer does not. Passivation in natural environments such as air, water and soil at moderate pH is seen in such materials as aluminium, stainless steel, titanium, and silicon.

text: Passivation is primarily determined by metallurgical and environmental factors. The effect of pH is summarized using Pourbaix diagrams, but many other factors are influential. Some conditions that inhibit passivation include high pH for aluminium and zinc, low pH or the presence of chloride ions for stainless steel, high temperature for titanium (in which case the oxide dissolves into the metal, rather than the electrolyte) and fluoride ions for silicon. On the other hand, unusual conditions may result in passivation of materials that are normally unprotected, as the alkaline environment of concrete does for steel rebar. Exposure to a liquid metal such as mercury or hot solder can often circumvent passivation mechanisms.

text: Corrosion in passivated materials[edit]

text: Passivation is extremely useful in mitigating corrosion damage, however even a high-quality alloy will corrode if its ability to form a passivating film is hindered.  Proper selection of the right grade of material for the specific environment is important for the long-lasting performance of this group of materials.  If breakdown occurs in the passive film due to chemical or mechanical factors, the resulting major modes of corrosion may include pitting corrosion, crevice corrosion, and stress corrosion cracking.

text: Pitting corrosion[edit]

text: Certain conditions, such as low concentrations of oxygen or high concentrations of species such as chloride which complete as anions, can interfere with a given alloy's ability to re-form a passivating film. In the worst case, almost all of the surface will remain protected, but tiny local fluctuations will degrade the oxide film in a few critical points. Corrosion at these points will be greatly amplified, and can cause corrosion pits of several types, depending upon conditions. While the corrosion pits only nucleate under fairly extreme circumstances, they can continue to grow even when conditions return to normal, since the interior of a pit is naturally deprived of oxygen and locally the pH decreases to very low values and the corrosion rate increases due to an autocatalytic process. In extreme cases, the sharp tips of extremely long and narrow corrosion pits can cause stress concentration to the point that otherwise tough alloys can shatter; a thin film pierced by an invisibly small hole can hide a thumb sized pit from view. These problems are especially dangerous because they are difficult to detect before a part or structure fails. Pitting remains among the most common and damaging forms of corrosion in passivated alloys,[citation needed] but it can be prevented by control of the alloy's environment.

text: Pitting results when a small hole, or cavity, forms in the metal, usually as a result of de-passivation of a small area. This area becomes anodic, while part of the remaining metal becomes cathodic, producing a localized galvanic reaction. The deterioration of this small area penetrates the metal and can lead to failure. This form of corrosion is often difficult to detect due to the fact that it is usually relatively small and may be covered and hidden by corrosion-produced compounds.

text: Weld decay and knifeline attack[edit]

text: Stainless steel can pose special corrosion challenges, since its passivating behavior relies on the presence of a major alloying component (chromium, at least 11.5%). Because of the elevated temperatures of welding and heat treatment, chromium carbides can form in the grain boundaries of stainless alloys. This chemical reaction robs the material of chromium in the zone near the grain boundary, making those areas much less resistant to corrosion. This creates a galvanic couple with the well-protected alloy nearby, which leads to "weld decay" (corrosion of the grain boundaries in the heat affected zones) in highly corrosive environments. This process can seriously reduce the mechanical strength of welded joints over time.

text: A stainless steel is said to be "sensitized" if chromium carbides are formed in the microstructure. A typical microstructure of a normalized type 304 stainless steel shows no signs of sensitization, while a heavily sensitized steel shows the presence of grain boundary precipitates. The dark lines in the sensitized microstructure are networks of chromium carbides formed along the grain boundaries.[3]

text: Special alloys, either with low carbon content or with added carbon "getters" such as titanium and niobium (in types 321 and 347, respectively), can prevent this effect, but the latter require special heat treatment after welding to prevent the similar phenomenon of "knifeline attack". As its name implies, corrosion is limited to a very narrow zone adjacent to the weld, often only a few micrometers across, making it even less noticeable.

text: Crevice corrosion[edit]

text: Crevice corrosion is a localized form of corrosion occurring in confined spaces (crevices), to which the access of the working fluid from the environment is limited. Formation of a differential aeration cell leads to corrosion inside the crevices. Examples of crevices are gaps and contact areas between parts, under gaskets or seals, inside cracks and seams, spaces filled with deposits and under sludge piles.

text: Crevice corrosion is influenced by the crevice type (metal-metal, metal-nonmetal), crevice geometry (size, surface finish), and metallurgical and environmental factors. The susceptibility to crevice corrosion can be evaluated with ASTM standard procedures. A critical crevice corrosion temperature is commonly used to rank a material's resistance to crevice corrosion.

text: Microbial corrosion[edit]

text: Microbial corrosion, or commonly known as microbiologically influenced corrosion (MIC), is a corrosion caused or promoted by microorganisms, usually chemoautotrophs. It can apply to both metallic and non-metallic materials, in the presence or absence of oxygen. Sulfate-reducing bacteria are active in the absence of oxygen (anaerobic); they produce hydrogen sulfide, causing sulfide stress cracking. In the presence of oxygen (aerobic), some bacteria may directly oxidize iron to iron oxides and hydroxides, other bacteria oxidize sulfur and produce sulfuric acid causing biogenic sulfide corrosion. Concentration cells can form in the deposits of corrosion products, leading to localized corrosion.

text: Accelerated low-water corrosion (ALWC) is a particularly aggressive form of MIC that affects steel piles in seawater near the low water tide mark. It is characterized by an orange sludge, which smells of hydrogen sulfide when treated with acid. Corrosion rates can be very high and design corrosion allowances can soon be exceeded leading to premature failure of the steel pile.[5] Piles that have been coated and have cathodic protection installed at the time of construction are not susceptible to ALWC. For unprotected piles, sacrificial anodes can be installed locally to the affected areas to inhibit the corrosion or a complete retrofitted sacrificial anode system can be installed. Affected areas can also be treated using cathodic protection, using either sacrificial anodes or applying current to an inert anode to produce a calcareous deposit, which will help shield the metal from further attack.

text: High-temperature corrosion[edit]

text: High-temperature corrosion is chemical deterioration of a material (typically a metal) as a result of heating. This non-galvanic form of corrosion can occur when a metal is subjected to a hot atmosphere containing oxygen, sulfur, or other compounds capable of oxidizing (or assisting the oxidation of) the material concerned. For example, materials used in aerospace, power generation and even in car engines have to resist sustained periods at high temperature in which they may be exposed to an atmosphere containing potentially highly corrosive products of combustion.

text: The products of high-temperature corrosion can potentially be turned to the advantage of the engineer. The formation of oxides on stainless steels, for example, can provide a protective layer preventing further atmospheric attack, allowing for a material to be used for sustained periods at both room and high temperatures in hostile conditions. Such high-temperature corrosion products, in the form of compacted oxide layer glazes, prevent or reduce wear during high-temperature sliding contact of metallic (or metallic and ceramic) surfaces.

text: Metal dusting[edit]

text: Metal dusting is a catastrophic form of corrosion that occurs when susceptible materials are exposed to environments with high carbon activities, such as synthesis gas and other high-CO environments. The corrosion manifests itself as a break-up of bulk metal to metal powder. The suspected mechanism is firstly the deposition of a graphite layer on the surface of the metal, usually from carbon monoxide (CO) in the vapor phase. This graphite layer is then thought to form metastable M3C species (where M is the metal), which migrate away from the metal surface. However, in some regimes no M3C species is observed indicating a direct transfer of metal atoms into the graphite layer.

text: Protection from corrosion[edit]

text: Various treatments are used to slow corrosion damage to metallic objects which are exposed to the weather, salt water, acids, or other hostile environments. Some unprotected metallic alloys are extremely vulnerable to corrosion, such as those used in neodymium magnets, which can spall or crumble into powder even in dry, temperature-stable indoor environments unless properly treated to discourage corrosion.

text: Surface treatments[edit]

text: When surface treatments are used to retard corrosion, great care must be taken to ensure complete coverage, without gaps, cracks, or pinhole defects. Small defects can act as an "Achilles' heel", allowing corrosion to penetrate the interior and causing extensive damage even while the outer protective layer remains apparently intact for a period of time.

text: Applied coatings[edit]

text: Plating, painting, and the application of enamel are the most common anti-corrosion treatments. They work by providing a barrier of corrosion-resistant material between the damaging environment and the structural material. Aside from cosmetic and manufacturing issues, there may be tradeoffs in mechanical flexibility versus resistance to abrasion and high temperature. Platings usually fail only in small sections, but if the plating is more noble than the substrate (for example, chromium on steel), a galvanic couple will cause any exposed area to corrode much more rapidly than an unplated surface would. For this reason, it is often wise to plate with active metal such as zinc or cadmium.

text: Painting either by roller or brush is more desirable for tight spaces; spray would be better for larger coating areas such as steel decks and waterfront applications. Flexible polyurethane coatings, like Durabak-M26 for example, can provide an anti-corrosive seal with a highly durable slip resistant membrane. Painted coatings are relatively easy to apply and have fast drying times although temperature and humidity may cause dry times to vary.

text: Reactive coatings[edit]

text: If the environment is controlled (especially in recirculating systems), corrosion inhibitors can often be added to it. These chemicals form an electrically insulating or chemically impermeable coating on exposed metal surfaces, to suppress electrochemical reactions. Such methods make the system less sensitive to scratches or defects in the coating, since extra inhibitors can be made available wherever metal becomes exposed. Chemicals that inhibit corrosion include some of the salts in hard water (Roman water systems are famous for their mineral deposits), chromates, phosphates, polyaniline, other conducting polymers and a wide range of specially-designed chemicals that resemble surfactants (i.e. long-chain organic molecules with ionic end groups).

text: Anodization[edit]

text: Aluminium alloys often undergo a surface treatment. Electrochemical conditions in the bath are carefully adjusted so that uniform pores, several nanometers wide, appear in the metal's oxide film. These pores allow the oxide to grow much thicker than passivating conditions would allow. At the end of the treatment, the pores are allowed to seal, forming a harder-than-usual surface layer. If this coating is scratched, normal passivation processes take over to protect the damaged area.

text: Anodizing is very resilient to weathering and corrosion, so it is commonly used for building facades and other areas where the surface will come into regular contact with the elements. While being resilient, it must be cleaned frequently. If left without cleaning, panel edge staining will naturally occur. Anodization is the process of converting an anode into cathode by bringing a more active anode in contact with it.

text: Biofilm coatings[edit]

text: A new form of protection has been developed by applying certain species of bacterial films to the surface of metals in highly corrosive environments. This process increases the corrosion resistance substantially. Alternatively, antimicrobial-producing biofilms can be used to inhibit mild steel corrosion from sulfate-reducing bacteria.[6]

text: Controlled permeability formwork[edit]

text: Controlled permeability formwork (CPF) is a method of preventing the corrosion of reinforcement by naturally enhancing the durability of the cover during concrete placement. CPF has been used in environments to combat the effects of carbonation, chlorides, frost and abrasion.

text: Cathodic protection[edit]

text: Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell. Cathodic protection systems are most commonly used to protect steel, and pipelines and tanks; steel pier piles, ships, and offshore oil platforms.

text: Sacrificial anode protection[edit]

text: For effective CP, the potential of the steel surface is polarized (pushed) more negative until the metal surface has a uniform potential. With a uniform potential, the driving force for the corrosion reaction is halted. For galvanic CP systems, the anode material corrodes under the influence of the steel, and eventually it must be replaced. The polarization is caused by the current flow from the anode to the cathode, driven by the difference in electrode potential between the anode and the cathode.

text: Impressed current cathodic protection[edit]

text: For larger structures, galvanic anodes cannot economically deliver enough current to provide complete protection. Impressed current cathodic protection (ICCP) systems use anodes connected to a DC power source (such as a cathodic protection rectifier). Anodes for ICCP systems are tubular and solid rod shapes of various specialized materials. These include high silicon cast iron, graphite, mixed metal oxide or platinum coated titanium or niobium coated rod and wires.

text: Anodic protection[edit]

text: Anodic protection impresses anodic current on the structure to be protected (opposite to the cathodic protection). It is appropriate for metals that exhibit passivity (e.g. stainless steel) and suitably small passive current over a wide range of potentials. It is used in aggressive environments, such as solutions of sulfuric acid.

text: Rate of corrosion[edit]

text: A simple test for measuring corrosion is the weight loss method.[7] The method involves exposing a clean weighed piece of the metal or alloy to the corrosive environment for a specified time followed by cleaning to remove corrosion products and weighing the piece to determine the loss of weight. The rate of corrosion (R) is calculated as

text:
where k is a constant,
W is the weight loss of the metal in time t, A is the surface area of the metal exposed, and ρ is the density of the metal (in g/cm³).

text: Other common expressions for the corrosion rate is penetration depth and change of mechanical properties.

text: Economic impact[edit]

text: In 2002, the US Federal Highway Administration released a study titled "Corrosion Costs and Preventive Strategies in the United States" on the direct costs associated with metallic corrosion in the US industry. In 1998, the total annual direct cost of corrosion in the U.S. was ca. $276 billion (ca. 3.2% of the US gross domestic product).[8] Broken down into five specific industries, the economic losses are $22.6 billion in infrastructure; $17.6 billion in production and manufacturing; $29.7 billion in transportation; $20.1 billion in government; and $47.9 billion in utilities.[9]

text: Rust is one of the most common causes of bridge accidents. As rust has a much higher volume than the originating mass of iron, its build-up can also cause failure by forcing apart adjacent parts. It was the cause of the collapse of the Mianus river bridge in 1983, when the bearings rusted internally and pushed one corner of the road slab off its support. Three drivers on the roadway at the time died as the slab fell into the river below. The following NTSB investigation showed that a drain in the road had been blocked for road re-surfacing, and had not been unblocked; as a result, runoff water penetrated the support hangers. Rust was also an important factor in the Silver Bridge disaster of 1967 in West Virginia, when a steel suspension bridge collapsed within a minute, killing 46 drivers and passengers on the bridge at the time.

text: Similarly, corrosion of concrete-covered steel and iron can cause the concrete to spall, creating severe structural problems. It is one of the most common failure modes of reinforced concrete bridges. Measuring instruments based on the half-cell potential can detect the potential corrosion spots before total failure of the concrete structure is reached.

text: Until 20–30 years ago, galvanized steel pipe was used extensively in the potable water systems for single and multi-family residents as well as commercial and public construction. Today, these systems have long ago consumed the protective zinc and are corroding internally resulting in poor water quality and pipe failures.[10]  The economic impact on homeowners, condo dwellers, and the public infrastructure is estimated at 22 billion dollars as the insurance industry braces for a wave of claims due to pipe failures.

text: Corrosion in nonmetals[edit]

text: Most ceramic materials are almost entirely immune to corrosion. The strong chemical bonds that hold them together leave very little free chemical energy in the structure; they can be thought of as already corroded. When corrosion does occur, it is almost always a simple dissolution of the material or chemical reaction, rather than an electrochemical process. A common example of corrosion protection in ceramics is the lime added to soda-lime glass to reduce its solubility in water; though it is not nearly as soluble as pure sodium silicate, normal glass does form sub-microscopic flaws when exposed to moisture. Due to its brittleness, such flaws cause a dramatic reduction in the strength of a glass object during its first few hours at room temperature.

text: Corrosion of polymers[edit]

text: Polymer degradation involves several complex and often poorly understood physiochemical processes. These are strikingly different from the other processes discussed here, and so the term "corrosion" is only applied to them in a loose sense of the word. Because of their large molecular weight, very little entropy can be gained by mixing a given mass of polymer with another substance, making them generally quite difficult to dissolve. While dissolution is a problem in some polymer applications, it is relatively simple to design against.

text: A more common and related problem is "swelling", where small molecules infiltrate the structure, reducing strength and stiffness and causing a volume change. Conversely, many polymers (notably flexible vinyl) are intentionally swelled with plasticizers, which can be leached out of the structure, causing brittleness or other undesirable changes.

text: The most common form of degradation, however, is a decrease in polymer chain length. Mechanisms which break polymer chains are familiar to biologists because of their effect on DNA: ionizing radiation (most commonly ultraviolet light), free radicals, and oxidizers such as oxygen, ozone, and chlorine. Ozone cracking is a well-known problem affecting natural rubber for example. Plastic additives can slow these process very effectively, and can be as simple as a UV-absorbing pigment (e.g. titanium dioxide or carbon black). Plastic shopping bags often do not include these additives so that they break down more easily as ultrafine particles of litter.

text: Corrosion of glasses[edit]

text: Glass is characterized by a high degree of corrosion-resistance. Because of its high water-resistance it is often used as primary packaging material in the pharma industry since most medicines are preserved in a watery solution.[11] Besides its water-resistance, glass is also very robust when being exposed to chemically aggressive liquids or gases. While other materials like metal or plastics quickly reach their limits, special glass-types can easily hold up.

text: Glass disease is the corrosion of silicate glasses in aqueous solutions. It is governed by two mechanisms: diffusion-controlled leaching (ion exchange) and hydrolytic dissolution of the glass network.[12] Both mechanisms strongly depend on the pH of contacting solution: the rate of ion exchange decreases with pH as 10−0.5pH whereas the rate of hydrolytic dissolution increases with pH as 100.5pH.[13]

text: Mathematically, corrosion rates of glasses are characterized by normalized corrosion rates of elements NRi (g/cm2·d) which are determined as the ratio of total amount of released species into the water Mi (g) to the water-contacting surface area S (cm2), time of contact t (days) and weight fraction content of the element in the glass fi:

text:
The overall corrosion rate is a sum of contributions from both mechanisms (leaching + dissolution) NRi=NRxi+NRh.
Diffusion-controlled leaching (ion exchange) is characteristic of the initial phase of corrosion and involves replacement of alkali ions in the glass by a hydronium (H3O+) ion from the solution. It causes an ion-selective depletion of near surface layers of glasses and gives an inverse square root dependence of corrosion rate with exposure time. The diffusion-controlled normalized leaching rate of cations from glasses (g/cm2·d) is given by:

text: where t is time, Di is the i-th cation effective diffusion coefficient (cm2/d), which depends on pH of contacting water as Di = Di0·10–pH, and ρ is the density of the glass (g/cm3).

text: Glass network dissolution is characteristic of the later phases of corrosion and causes a congruent release of ions into the water solution at a time-independent rate in dilute solutions (g/cm2·d):

text:
where rh is the stationary hydrolysis (dissolution) rate of the glass (cm/d).
In closed systems the consumption of protons from the aqueous phase increases the pH and causes a fast transition to hydrolysis.[14] However, a further saturation of solution with silica impedes hydrolysis and causes the glass to return to an ion-exchange, e.g. diffusion-controlled regime of corrosion.

text: In typical natural conditions normalized corrosion rates of silicate glasses are very low and are of the order of 10−7–10−5 g/(cm2·d). The very high durability of silicate glasses in water makes them suitable for hazardous and nuclear waste immobilisation.

text: Glass corrosion tests[edit]

text: There exist numerous standardized procedures for measuring the corrosion (also called chemical durability) of glasses in neutral, basic, and acidic environments, under simulated environmental conditions, in simulated body fluid, at high temperature and pressure,[16] and under other conditions.

text: The standard procedure ISO 719[17] describes a test of the extraction of water-soluble basic compounds under neutral conditions: 2 g of glass, particle size 300–500 μm, is kept for 60 min in 50 ml de-ionized water of grade 2 at 98 °C; 25 ml of the obtained solution is titrated against 0.01 mol/l HCl solution. The volume of HCl required for neutralization is classified according to the table below.

text:
Amount of 0.01M HCl needed to neutralize extracted basic oxides, ml

Extracted Na2Oequivalent, μg

Hydrolyticclass

< 0.1

< 31

1

0.1-0.2

31-62

2

0.2-0.85

62-264

3

0.85-2.0

264-620

4

2.0-3.5

620-1085

5

> 3.5

> 1085

> 5

tag: table

text: The standardized test ISO 719 is not suitable for glasses with poor or not extractable alkaline components, but which are still attacked by water, e.g. quartz glass, B2O3 glass or P2O5 glass.

text: Usual glasses are differentiated into the following classes:

text: Hydrolytic class 1 (Type I):

text: This class, which is also called neutral glass, includes borosilicate glasses (e.g. Duran, Pyrex, Fiolax).

text: Glass of this class contains essential quantities of boron oxides, aluminium oxides and alkaline earth oxides. Through its composition neutral glass has a high resistance against temperature shocks and the highest hydrolytic resistance. Against acid and neutral solutions it shows high chemical resistance, because of its poor alkali content against alkaline solutions.

text: Hydrolytic class 2 (Type II):

text: This class usually contains sodium silicate glasses with a high hydrolytic resistance through surface finishing. Sodium silicate glass is a silicate glass, which contains alkali- and alkaline earth oxide and primarily sodium oxide and Calcium oxide.

text: Hydrolytic class 3 (Type III):

text: Glass of the 3rd hydrolytic class usually contains sodium silicate glasses and has a mean hydrolytic resistance, which is two times poorer than of type 1 glasses.

text: Acid class DIN 12116 and alkali class DIN 52322 (ISO 695) are to be distinguished from the hydrolytic class DIN 12111 (ISO 719).


document_title: List of European Cup and UEFA Champions League top scorers

question_text: who is d highest goal scorer in uefa champions league

text: All-time top scorers

text:
Player

Country

Goals

Apps

Ratio

Years

Clubs

1

Cristiano Ronaldo

 Portugal

120[a]

153

0.78

2003–

Manchester United Real Madrid

2

Lionel Messi

 Argentina

100

125

0.8

2005–

Barcelona

3

Raúl

 Spain

71

142

0.5

1995–2011

Real MadridSchalke 04

4

Ruud van Nistelrooy

 Netherlands

56[b]

73

0.77

1998–2009

PSV EindhovenManchester UnitedReal Madrid

Karim Benzema

 France

56

104

0.54

2006–

Lyon Real Madrid

6

Thierry Henry

 France

50[c]

112

0.45

1997–2012

MonacoArsenalBarcelona

7

Alfredo Di Stéfano

 Argentina

49

58

0.84

1955–1964

Real Madrid

8

Andriy Shevchenko

 Ukraine

48[d]

100

0.48

1994–2012

Dynamo KyivMilanChelsea

Zlatan Ibrahimović

 Sweden

48[e]

120

0.4

2001–2018

AjaxJuventusInternazionaleBarcelonaMilanParis Saint-GermainManchester United

10

Eusébio

 Portugal

47

63

0.75

1961–1974

Benfica

11

Filippo Inzaghi

 Italy

46[f]

81

0.57

1997–2012

JuventusMilan

12

Robert Lewandowski

 Poland

45

70

0.64

2011–

Borussia DortmundBayern Munich

13

Didier Drogba

 Ivory Coast

44

92

0.48

2003–2015

MarseilleChelseaGalatasaray

14

Alessandro Del Piero

 Italy

42[g]

89

0.47

1995–2009

Juventus

Thomas Müller

 Germany

42

97

0.43

2008–

Bayern Munich

16

Ferenc Puskás

 Hungary

35

41[4]

0.85

1956–1966

Budapest HonvédReal Madrid

17

Gerd Müller

 West Germany

34

35[4]

0.97

1969–1977

Bayern Munich

18

Francisco Gento

 Spain

32

88

0.36

1955–1969

Real Madrid

Edinson Cavani

 Uruguay

32

52[5]

0.62

2011–

NapoliParis Saint-Germain

20

Sergio Agüero

 Argentina

31[h]

61

0.51

2008–

Atlético MadridManchester City

21

Samuel Eto'o

 Cameroon

30[i]

78

0.38

1999–2014

MallorcaBarcelonaInternazionaleChelsea

Wayne Rooney

 England

30[j]

85

0.35

2004–2016

Manchester United

Kaká

 Brazil

30

86

0.35

2003–2014

MilanReal Madrid

Fernando Morientes

 Spain

30[k]

88

0.34

1997–2009

Real MadridMonacoLiverpoolValencia

25

David Trezeguet

 France

29[l]

58

0.5

1997–2009

MonacoJuventus

Roy Makaay

 Netherlands

29

61

0.48

2000–2007

Deportivo La CoruñaBayern Munich

Patrick Kluivert

 Netherlands

29[m]

71

0.41

1994–2006

AjaxBarcelona

Arjen Robben

 Netherlands

29[n]

106

0.27

2002–

PSV EindhovenChelseaReal MadridBayern Munich

29

Jean-Pierre Papin

 France

28

37[4]

0.76

1989–1994

MarseilleMilanBayern Munich

Ryan Giggs

 Wales

28[o]

141

0.2

1993–2014

Manchester United

31

Neymar

 Brazil

27

47[6]

0.57

2013–

BarcelonaParis Saint-Germain

Rivaldo

 Brazil

27[p]

73

0.37

1997–2007

BarcelonaMilanOlympiacos

33

Mario Gómez

 Germany

26[q]

44[7]

0.59

2007–2013

StuttgartBayern Munich

34

Mário Jardel

 Brazil

25[r]

46[8]

0.54

1996–2001

PortoGalatasaray

Robin van Persie

 Netherlands

25[s]

59

0.42

2002–2014

ArsenalManchester United

Hernán Crespo

 Argentina

25[t]

65

0.38

1997–2007

ParmaLazioInternazionaleChelseaMilan

Giovane Élber

 Brazil

25[u]

69

0.36

1997–2004

Bayern MunichLyon

38

José Altafini

 Brazil

24

28[4]

0.86

1959–1976

MilanJuventus

Marco Simone

 Italy

24[v]

46[9]

0.52

1989–2001

MilanParis Saint-GermainMonaco

Luís Figo

 Portugal

24

103

0.23

1997–2009

BarcelonaReal MadridInternazionale

Paul Scholes

 England

24[w]

124

0.19

1994–2013

Manchester United

42

Jari Litmanen

 Finland

23

57

0.4

1993–2003

AjaxLiverpool

Frank Lampard

 England

23

105

0.22

2001–2015

ChelseaManchester City

44

Santillana

 Spain

22

46[10]

0.48

1971–1988

Real Madrid

Gonzalo Higuaín

 Argentina

22

75

0.29

2007–

Real MadridNapoliJuventus

46

José Torres

 Portugal

21

33[11]

0.64

1959–1971

Benfica

Luiz Adriano

 Brazil

21[x]

47[12]

0.45

2008–

Shakhtar DonetskSpartak Moscow

Amancio

 Spain

21

52

0.4

1962–1976

Real Madrid

Steven Gerrard

 England

21[y]

73

0.29

2001–2015

Liverpool

Claudio Pizarro

 Peru

21[z]

73

0.29

2001–2014

Bayern MunichWerder Bremen

text:
Jump up ^ Ronaldo additionally scored one goal[3] in four qualification matches.

Jump up ^ Van Nistelrooy additionally scored four goals in eight qualification matches.

Jump up ^ Henry additionally scored one goal in three qualification matches.

Jump up ^ Shevchenko additionally scored 11 goals in 16 qualification matches.

Jump up ^ Ibrahimović additionally scored one goal in four qualification matches.

Jump up ^ Inzaghi additionally scored four goals in four qualification matches.

Jump up ^ Del Piero additionally scored two goals in three qualification matches.

Jump up ^ Agüero additionally scored six goals in four qualification matches.

Jump up ^ Eto'o additionally scored three goals in four qualification matches.

Jump up ^ Rooney additionally scored four goals in three qualification matches.

Jump up ^ Morientes additionally scored six goals in 11 qualification matches.

Jump up ^ Trezeguet additionally scored three goals in three qualification matches.

Jump up ^ Kluivert additionally scored one goal in four qualification matches.

Jump up ^ Robben additionally scored one goal in one qualification match.

Jump up ^ Giggs additionally scored two goals in 10 qualification matches.

Jump up ^ Rivaldo additionally scored four goals in five qualification matches.

Jump up ^ Gómez additionally scored one goal in two qualification matches.

Jump up ^ Jardel additionally scored three goals in two qualification matches.

Jump up ^ Van Persie additionally scored two goals in nine qualification matches.

Jump up ^ Crespo additionally scored three goals in five qualification matches.

Jump up ^ Élber additionally scored two goals in four qualification matches.

Jump up ^ Simone additionally scored one goal in two qualification matches.

Jump up ^ Scholes additionally scored one goal in six qualification matches.

Jump up ^ Adriano additionally scored one goal in four qualification matches.

Jump up ^ Gerrard additionally scored nine goals in 14 qualification matches.

Jump up ^ Pizarro additionally scored three goals in four qualification matches.

tag: ol

text: Top scorers by seasons

text: The table below does not include goals scored in the qualification stage of the competition.[13]

text:
Season

Player

Country

Club

Goals

1955–56

Miloš Milutinović

 Yugoslavia

 Partizan

8

1956–57

Dennis Viollet

 England

 Manchester United

9

1957–58

Alfredo Di Stéfano

 Argentina

 Real Madrid

10

1958–59

Just Fontaine

 France

 Stade Reims

10

1959–60

Ferenc Puskás

 Hungary

 Real Madrid

12

1960–61

José Águas

 Portugal

 Benfica

11

1961–62

Heinz Strehl

 West Germany

 1. FC Nürnberg

8

1962–63

José Altafini

 Italy

 Milan

14

1963–64

Vladica Kovačević

 Yugoslavia

 Partizan

7

Sandro Mazzola

 Italy

 Internazionale

Ferenc Puskás

 Hungary

 Real Madrid

1964–65

Eusébio

 Portugal

 Benfica

9

José Torres

 Portugal

 Benfica

1965–66

Flórián Albert

 Hungary

 Ferencváros

7

Eusébio

 Portugal

 Benfica

1966–67

Jürgen Piepenburg

 East Germany

 Vorwärts Berlin

6

Paul Van Himst

 Belgium

 Anderlecht

1967–68

Eusébio

 Portugal

 Benfica

6

1968–69

Denis Law

 Scotland

 Manchester United

9

1969–70

Mick Jones

 England

 Leeds United

8

1970–71

Antonis Antoniadis

 Greece

 Panathinaikos

10

1971–72

Johan Cruyff

 Netherlands

 Ajax

5

Antal Dunai

 Hungary

 Újpesti Dózsa

Lou Macari

 Scotland

 Celtic

Silvester Takač

 Yugoslavia

 Standard Liège

1972–73

Gerd Müller

 West Germany

 Bayern Munich

11

1973–74

Gerd Müller

 West Germany

 Bayern Munich

8

1974–75

Gerd Müller

 West Germany

 Bayern Munich

5

Eduard Markarov

 Soviet Union

 Ararat Yerevan

1975–76

Jupp Heynckes

 West Germany

 Borussia Mönchengladbach

6

1976–77

Gerd Müller

 West Germany

 Bayern Munich

5

Franco Cucinotta

 Italy

 Zürich

1977–78

Allan Simonsen

 Denmark

 Borussia Mönchengladbach

5

1978–79

Claudio Sulser

 Switzerland

 Grasshopper

11

1979–80

Søren Lerby

 Denmark

 Ajax

10

1980–81

Terry McDermott

 England

 Liverpool

6

Graeme Souness

 Scotland

 Liverpool

Karl-Heinz Rummenigge

 West Germany

 Bayern Munich

1981–82

Dieter Hoeneß

 West Germany

 Bayern Munich

7

1982–83

Paolo Rossi

 Italy

 Juventus

6

1983–84

Viktor Sokol

 Soviet Union

 Dinamo Minsk

6

1984–85

Torbjörn Nilsson

 Sweden

 IFK Göteborg

7

Michel Platini

 France

 Juventus

1985–86

Torbjörn Nilsson

 Sweden

 IFK Göteborg

6

1986–87

Borislav Cvetković

 Yugoslavia

 Red Star Belgrade

7

1987–88

Gheorghe Hagi

 Romania

 Steaua Bucureşti

4

Jean-Marc Ferreri

 France

 Bordeaux

Rabah Madjer

 Algeria

 Porto

Ally McCoist

 Scotland

 Rangers

Míchel

 Spain

 Real Madrid

Rui Águas

 Portugal

 Benfica

1988–89

Marco van Basten

 Netherlands

 Milan

10

1989–90

Romário

 Brazil

 PSV Eindhoven

6

Jean-Pierre Papin

 France

 Marseille

1990–91

Peter Pacult

 Austria

 Tirol Innsbruck

6

Jean-Pierre Papin

 France

 Marseille

1991–92

Sergei Yuran

 Ukraine

 Benfica

7

Jean-Pierre Papin

 France

 Marseille

1992–93

Franck Sauzée

 France

 Marseille

5

1993–94

Hristo Stoichkov

 Bulgaria

 Barcelona

5

1994–95

George Weah

 Liberia

 Paris Saint-Germain

7

1995–96

Jari Litmanen

 Finland

 Ajax

9

1996–97

Milinko Pantić

 Yugoslavia

 Atlético Madrid

5

1997–98

Alessandro Del Piero

 Italy

 Juventus

10

1998–99

Andriy Shevchenko

 Ukraine

 Dynamo Kyiv

8

Dwight Yorke

 Trinidad and Tobago

 Manchester United

1999–00

Mário Jardel

 Brazil

 Porto

10

Rivaldo

 Brazil

 Barcelona

Raúl

 Spain

 Real Madrid

2000–01

Raúl

 Spain

 Real Madrid

7

2001–02

Ruud van Nistelrooy

 Netherlands

 Manchester United

10

2002–03

Ruud van Nistelrooy

 Netherlands

 Manchester United

12

2003–04

Fernando Morientes

 Spain

 Monaco

9

2004–05

Ruud van Nistelrooy

 Netherlands

 Manchester United

8

2005–06

Andriy Shevchenko

 Ukraine

 Milan

9

2006–07

Kaká

 Brazil

 Milan

10

2007–08

Cristiano Ronaldo

 Portugal

 Manchester United

8

2008–09

Lionel Messi

 Argentina

 Barcelona

9

2009–10

Lionel Messi

 Argentina

 Barcelona

8

2010–11

Lionel Messi

 Argentina

 Barcelona

12

2011–12

Lionel Messi

 Argentina

 Barcelona

14

2012–13

Cristiano Ronaldo

 Portugal

 Real Madrid

12

2013–14

Cristiano Ronaldo

 Portugal

 Real Madrid

17

2014–15

Neymar

 Brazil

 Barcelona

10

Cristiano Ronaldo

 Portugal

 Real Madrid

Lionel Messi

 Argentina

 Barcelona

2015–16

Cristiano Ronaldo

 Portugal

 Real Madrid

16

2016–17

Cristiano Ronaldo

 Portugal

 Real Madrid

12

2017–18

Cristiano Ronaldo

 Portugal

 Real Madrid

15

text: By player

text:
Player

Titles

Seasons

 Cristiano Ronaldo
7
2007–08, 2012–13, 2013–14, 2014–15, 2015–16, 2016–17, 2017–18

 Lionel Messi
5
2008–09, 2009–10, 2010–11, 2011–12, 2014–15

 Gerd Müller
4
1972–73, 1973–74, 1974–75, 1976–77

 Eusébio
3
1964–65, 1965–66, 1967–68

 Jean-Pierre Papin
1989–90, 1990–91, 1991–92

 Ruud van Nistelrooy
2001–02, 2002–03, 2004–05

 Ferenc Puskás
2
1959–60, 1963–64

 Torbjörn Nilsson
1984–85, 1985–86

 Raúl
1999–00, 2000–01

 Andriy Shevchenko
1998–99, 2005–06

text: By country

text:
Country

Titles

Seasons

 Portugal
13
1960–61, 1964–65,[a] 1964–65,[a] 1965–66, 1967–68, 1987–88, 2007–08, 2012–13, 2013–14, 2014–15, 2015–16, 2016–17, 2017–18

 West Germany
8
1961–62, 1972–73, 1973–74, 1974–75, 1975–76, 1976–77, 1980–81, 1981–82

 France
7
1958–59, 1984–85, 1987–88, 1989–90, 1990–91, 1991–92, 1992–93

 Argentina
6
1957–58, 2008–09, 2009–10, 2010–11, 2011–12, 2014–15

 Yugoslavia
5
1955–56, 1963–64, 1971–72, 1986–87, 1996–97

 Italy
1962–63, 1963–64, 1976–77, 1982–83, 1997–98

 Netherlands
1971–72, 1988–89, 2001–02, 2002–03, 2004–05

 Brazil
1989–90, 1999–2000,[b] 1999–2000,[b] 2006–07, 2014–15

 Hungary
4
1959–60, 1963–64, 1965–66, 1971–72

 Scotland
1968–69, 1971–72, 1980–81, 1987–88

 Spain
1987–88, 1999–2000, 2000–01, 2003–04

 England
3
1956–57, 1969–70, 1980–81

 Ukraine
1991–92, 1998–99, 2005–06

 Soviet Union
2
1974–75, 1983–84

 Denmark
1977–78, 1979–80

 Sweden
1984–85, 1985–86

text:
^ Jump up to: a b Two Portuguese players were joint top scorers in this season.

^ Jump up to: a b Two Brazilian players were joint top scorers in this season.