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Effect Of Al Content In The High Power Engine Piston Ring On The Performance Of AlCrN Coating

Posted on:2013-04-10Degree:MasterType:Thesis
Country:ChinaCandidate:D C WeiFull Text:PDF
GTID:2231330377953745Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
Multi arc ion plating is one of the physical vapor deposition method, which mainly usedfor preparing many kinds of high hardness and high abrasive resistance compound coatings orhigh-melting metal coating. Because of this method has little pollution to environment, itreceives word-wide high attention since its beginning, and is in rapid change, also occupiesthe important position in the coating technology so far.As a kind of high performance coatings, AlCrN coating has high hardness, highoxidation resistance, low friction coefficient and etc, and many properties are better than theproperties that CrN and TiAlN coatings have, so it has a wide range of applications in tools.Inorder to extend the applications of AlCrN coating, in this experiment, multi arc ion platingtechnology was used to prepare heat resisting and wearable AlCrN coating on the surface ofthe cast iron packing rings,and the properties were tested and researched.In this experiment, through controlling the matrix pulse voltage bias, aluminum targetcurrent, deposition of time to change the content of Al in the coatings,and studied the impactof the content change of Al to the coating propertiies,mainly studied the impacts to therubbingfactor of coatings from surface morphology, mechanical properties (microhardness,membrane-based bond strength), microstructure (phase composition, growth orientation, thedensity of coating, etc)and the content of Al.The test results showed that: AlCrN coatings that prepared by bias voltage as-100V、-200V、-400V and-600V,were analysed by metallographic microscope,the coating surfacemorphology is level, and compact structure when the bias voltaage was-100V,but as theincrease of bias voltage, coating surface morphology changed,the coating surface becomejagged, friction coefficient will then increased too when the bias voltage increased to-600V.After XRD analysis,obtained that phase compositions of coatings were AlN、CrN and Cr2N,as the bias voltage increased,the peak of AlN phase had the trend to become low and wide,while continue increasing the bias voltage the growth of AlN orientation was not obvious, butCr2N had preferred orientation growth trend. In addition, with the rise of bias, the coatinghardness and film the bond strength were reduced.Also the phase compositions of AlCrNwere AlN, CrN and Cr2N when in different aluminum target currents, whith the rise ofaluminum target current, the coating’s content of Al had increased rend,moreover themicrohardness of coatings frst increased then decreased with the increase of aluminum targetcurrent,it’s just that in the coating contained large amount of pure Al particles,and pure Aldroplets would reduce the coating hardness, but Al droplets can reduce growth stress incoatings,so the bond strength of coatings was higher when the Al content was higher.Al content on the influence of the coating is very important, the test results showedthat:when the content of Al is low, the coating surface morphology is relatively smooth, whenthe content of Al increases coating surface has big particles of Al mosaic,and the surface become rough. The content of Al directly influences the coating microhardness,according tothe test that when the content of Al is less than40at.%,the micro hardness of coating is withthe increase of content of Al increased, and the friction factor is with the increase of thecontent of Al reduced, the best friction factor is between0.29~0.38.
Keywords/Search Tags:Multi arc ion plating, iron packing ring, AlCrN coating, the content of Al, combination property
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