Preparation And High Temperature Oxidation Resistance Of CrAlSiN Hard Coating By Magnetron Sputtering

As the latest third-generation film system,CrAlSiN Nano-composite hard film has many excellent properties that the previous two generations of hard film did not have.Its hardness,elastic modulus,toughness,high-temperature oxidation resistance and thermal stability properties have been greatly improved?extending the service life of coated tool and even die film.In this paper,CrAlSiN hard film was prepared by magnetron sputtering.Based on the kev intrinsic characteristics of the film,such as hardness,modulus and phase structure.the optimal process experiment of film preparation was carried out;On this basis,according to the high temperature environment temperature of high speed cutting tool,dry friction or refractory material,atmospheric and vacuum heat treatment were carried out respectively to study the oxidation resistance and thermal stability of the film.On the basis of the previous work of the research group,CrAlSiN hard film was deposited on the surface of high-speed steel and cemented carbide.and the Si content was 7.18/8.06at.%,respectively.The experimental design of substrate pretreatment process,that is.glow cleaning followed by Ar ion bombardment for 2 hours,to improve the film base adhesion and film deposition structure;Sputtering after high temperature under the atmospheric and vacuum heat treatment(700oC,800oC.900OC and 1000?),the film samples by scanning electron microscope and energy spectrometer,X-ray diffractometer,nano indentation,laser confocal microscope,Zeiss metallographic microscope and other means of characterization and analysis.The maximum hardness and elastic modulus of CrAlSiN film based on high-speed steel can reach 27.17GPa/293.8GPa.For CrAlSiN thin films based on cemented carbide,the maximum hardness and elastic modulus can reach 27.07GPaj449.7GPa.The surface of the thin film is flat and dense.The phase structure of CrAlSiN thin film prepared by the two substrates is mainly(111)and(200)oriented CrAIN plane-centered cubic structure.The diffraction peak(201)of Si4N3 hexagon structure was found in the CrAlSiN thin film with cemented carbide as the matrix.Thls indicates that Si4N3 In the cemented carbide film structure changes the amorphous structure ot the film layer.thus changing the structure of the film layer and the composition of Si4N3 in the nanocomposite structure with the high hardness and surface energy of the matrix.resulting in the improvement of the hardness and modulus of the film layer.After bombardment,the membrane base adhesion was significantly increased.For high speed steel substrate CrAlSiN film after heat treatment atmosphere at 800?phase structure is stable and smooth;900? when the six-party structure of AIN and CrZO3 and Al2O3 oxide;1000?,the substrate oxidization,Cr2O3.Al2O3 content is less,surface membrane layer uplift,oxidation degree aggravating;For cemented carbide substrate CrAlSiN film after heat treatment atmosphere,700?when the Cr oxide phase,crack of thin film;800? CrZO3 diffraction peak is abate,crack density and found that matrix oxide;In 900? Cr3O4 and Al2O3 phase;1000?(201)diffraction peak of Si4N3 still exists,and ordering,oxide phase structure tend to be more diversified and film has complete failure.For cemented carbide substrate CrAlSiN film after vacuum heat treatment,700?when there were no changes in phase structure,the performance is stable;800? CrAlN weakened(111)diffraction peak width,Si4N3(201)diffraction peak enhancement,appeared crack;900? when CrN to CrZN,N,Cr,Si element content in Al element content;1000? when the hardness.modulus,slash,in great change of membrane structure.