Preparation And Properties Of Four-components Nitride Hard Reactive Films

In this topic, Ti-25Nb(atomic percentage) alloy target with pure Zr target or pure Cr targetdeposited on high speed steel to make (Ti, Zr, Nb)N or (Cr, Ti, Nb)N multi-constituent films bycontrolling the N2and Ar partial pressure with the arc ion plating technology in order to ensurethe hardness of the obtained multi-component hard nitride reactive films of other elements asbasic alloy elements reached and even passed the hardness of TiN as basic elements or not. TheN2partial pressure was increased step by step from0Pa to3.010-1Pa to obtain the N-gradientdistribution in the direction of film growth to make the (Ti, Zr, Nb)N and (Cr, Ti, Nb)N hardgradient films.The as-deposited two series of (Ti, Zr, Nb)N and (Cr, Ti, Nb)N hard films weresystematically investigated in terms of film composition, phase structure, micro-hardness,adhesion, wearing resistance and thermal shock resistance. The very similar surfacemorphology was obtained on surface of two series of films. There were micro-droplets indimension less than5μm on the surface.But the number of the micro-droplets was small. Thethickness of (Ti, Zr, Nb)N and (Cr, Ti, Nb)N films dropped in0.7μm~1.1μm. The fractured-cross-section microstructure was dense columnar microstructure. The deposition rate decreasedslightly with increasing bias voltage. The analysis of the results that (XRD) technologyperformed showed that (Cr, Ti, Nb)N and (Ti, Zr, Nb)N films were both with the f.c.c structure(B1-NaCl type) of TiN. The preferred growth orientation was (111) plane expect (Ti, Zr, Nb)Nand the preferred orientation was (220) plane in (Ti, Zr, Nb)N single-layer film. Moreover,the Ncontents in two series of (Ti, Zr, Nb)N and (Cr, Ti, Nb)N films were both bigger than50percentage. The N contents have some influence on the preferred growth orientation of the filmsand the diffraction peak was influenced by bias voltage.The test of two series of multiple films’ micro-hardness and adhesive force results showedthat (Cr, Ti, Nb)N and(Ti, Zr, Nb)N as two series of gradient films,their comprehensive properties are both better than (Cr, Ti, Nb)N and (Ti, Zr, Nb)N as two series of single-layer film.Their hardness was up to3300HV and adhesive strength was higher than200N. However, the(Ti, Zr, Nb)N and (Cr, Ti, Nb)N as two series of single-layer film, their hardness was up to3000HV and adhesive strength was higher than140N.The frictional wear tests showed that the friction coefficient of (Ti, Zr, Nb)N as the multiplefilms were all smaller than (Cr, Ti, Nb)N as the multiple films’ in the same frictional parameterand deposition test. In other words, the wear resistance of (Ti, Zr, Nb)N multiple films werebetter than (Cr, Ti, Nb)N multiple films.The result of the thermal shock tests carried out at650℃showed that after a certainnumber of thermal shock cycling tests, the failure of two series of multiple films occurred intwo ways. The first one was that oxidized film peeled off easily. The second was that microcrack occurred on the film surface.(Cr, Ti, Nb)N gradient films failed in the way of cracksextending. However, the failure of (Cr, Ti, Nb)N single-layer film and (Ti, Zr, Nb)N multiplefilms were both the ways of the films peeling off. The thermal shock resistance of (Cr,Ti,Nb)Nmultiple films was better than (Ti, Zr, Nb)N multiple films. The thermal shock resistance of thegradient films in two series was better than single-layer film.