The Effect Of Y Incorporation On The Structure And Oxidation Resistance Of Cr–Al–N Films

CrAlN film received widespread attention as its high hardness,wear resistance,high resistance to oxidation and other excellent performance.And has been successfully used in tools,molds,aerospace and many other fields.However,with the development of science and technology,the fims' performance requirements are becoming higher and higher.This paper mainly studies the effects of Y and Sialloy elements on the properties of CrAlN films.CrAlYN films with different contents of Y,CrAlSiN films with differentcontents of Si and CrAlSiYN films were deposited on the high-speed steel substrates via magnetron sputtering,then high temperature oxidation and vacuum tests were conducted.The surface morphologies,chemical composition,phase structure,nano-hardness and elastic modulus of the films were analyzed with SEM,EDS,XRD and nano-indentation.The effects of Y and Si on films' hardness,elastic modulus,phase composition,thermal stability and antioxidant property were investigated,respectively.Films formed no new phase with Y addition,but the main orientation of(Cr,Al)N phase transformed from(200)to(111).Compared with CrAlN film,the hardness,elastic modulus and antioxidant property of the CrAlYN film with 0.41 at.% Y contentwere improved.But the films' performance decreased at 2.75 at.% and 3.94 at.% Y content.ForCrAlYN film,after high temperature oxidation test,intragranular O?Cr?Al?Fe andY were precipitated homogeneously.However,at grain boundary and large particle,O was rich,Al and Fe were undernourished.For CrAlSiN films,hardness and modulus were comparatively better when Si content was 2.75 at.%.The film had no signs of oxidation after heat treatment at 800? in air,So the film had good oxidation resistance.Cr2O3 and Al2O3 appeared after heat treatment at 900?,so the film had been oxidized.After heat treatment at 1000?,the adhesion of film and substrate weakened.And there were a large number of Fe2O3 and a small amount of Cr3 O phase,so the film was heavy oxidation.The hardness and modulus of CrAlSiYN film deposited by Cr30Al70 alloy target were far lower than CrAlSiN and CrAlYN films'.Compared with that,the hardness and modulus of CrAlSiYN film deposited by Cr50Al50 alloy target were improved significantly,but they were still lower than that of CrAlSiN and CrAlYN films.The high temperature oxidation resistance of CrAlSiYN film hadn't improved,After heat treatment at 1000?,CrAlSiYN film was oxidation failure compeletely.After heat treatment at 850? in vacuum,it had good heat-stability.When the vacuum heat treatment temperature raised to 950 ?and 1050?,the film surface appeared a large number of crack,and at 1050?,thefilm was raised.