Preparation And Properties Of Ti-Si-N Films And Ti-Si-N Compositional Gradient Films By Magnetron Sputtering

With the development of material science,the traditional TiC and TiN film material can not meet the requirements of cutting tool materials,Ti-Si-N film with high hardness,low friction coefficient,good thermal stability and chemical stability,other excellent characteristics,is very suitable for high-speed cutting tool surface protection and requirement of the modern mechanical industry,at present the application prospect is very wide in the film industry.Using magnetron sputtering technology,by adjusting the process parameters:the nitrogen flow,sputtering temperature,sputtering power,deposition time,gradient time,modulation period,and modulation ratio,on the 304 stainless steel substrate,a series of Ti-Si-N monolayers,Ti-Si-N compositional gradient film and TiN/TiSiN multilayered film were prepared on a 304 stainless steel substrate.The crystal structure and microstructure of samples were studied by Philips X ’Pert MPD automatic diffractometer and JDM-7001F field emission scanning electron microscope.The 401MVDTM micro-hardness tester and WS-25 type coating adhesion automatic scoring instrument were respectively the mechanical properties such as hardness,film-base adhesion and so on.The relationship between microstructure,crystal structure and mechanical properties was studied.(1)For single Ti-Si-N films,the effect of process parameters,such as nitrogen flow and sputtering temperature,on the structure and mechanical properties were investigated.With the increase of nitrogen flow,the characteristic peaks ofγ-Si3N4(511)appeared.and the hardness of the films increased at first and then decreased.When the nitrogen flow increased to 8 sccm(Ti-10Si(at%)target),grain size small,and the hardness(4181 HV)and the bonding force(41 N)reach to the maximum value,comprehensive performance had reached the best value of the film.With the increase of sputtering temperature,the characteristic diffraction peak of TiN(200)gradually increased.When the temperature was 300℃ the grain size of the film is obviously small and the density was higher.When the temperature was 300℃,The hardness of the two target sputtered films reached 3878 HV(Ti-10Si(at%)target)and 4181 HV.With the increase of sputtering power,the Ti-Si-N thin film was mainly composed of TiN in the diffraction pattern.When the power was increased to 600 W and 800 W,the grain of the film was fine and uniform.When the power was 800 W(Ti-20Si(at%)target),the hardness reaches a maximum of 4582 HV.With the increase of deposition time,the grain size was uniform and fine,and the hardness increased linearly.When the deposition time increased to 240 min(Ti-20Si(at%)target),the hardness increased to 4605 HV.(2)For the Ti-Si-N gradient film,the Ti,TiN,and γ-Si3N4 phases appear in the gradient film with increasing gradient time,and the surface morphology of the gradient film had little change.Hardness and binding force increase and then decreased with the increase of gradient time.When the gradient time was 90 min,the hardness reached 4558 HV and the binding force reached 44 N.Compared with the single film hardness increased 200 HV,the binding force increased by 18 N.(3)TiN,TiN,Ti2N and y-Si3N4 appeared in TiN/TiSiN multilayers.When the modulation ratio is 1:2,the surface morphology of films became cellular and the grain size was small.When the modulation period was 10.When the modulation period was 15 layers,the binding force increased with the increased of the modulation period,and then decreased.The bonding force reached 35 N.