Optimum Process And Microstructure Analysis Of 40Cr Surface (Ti, Al) N Films

As an important part of the transmission device,the gear loses the effectiveness becauseof broken teeth,wear and tear of tooth surface,surface pitting and tooth scuffing gluing in theprocess of use. In order to improve the performance and prolong the service life of the gear，people usually apply some heat treatments, such as quenching,nitridation and so on.Whichstrengthen gear surface in the industry. However,with the increase of requirements and thediversity of the forms of the gear losing effectiveness in industrial production,it’s verydifficult to use the heat treatment process only to meet the requirements of the actualperformance. Then the coating technology is put forward and applied in this condition.Theproper deposition process has been deterimined. The films with glabrous appearance andsmooth surface have been obtained under the conditions of the selected depositionprocesses.Technology parameters of thin film deposition is designed and optimized based onorthogonal test. People apply multi-arc ion plating to deposit in(Ti,Al)N,the super-hardceramic reaction film on the surface of the substrate---alloy steel40Cr. People observe thetopography and fractograph,analyze the surface components; analyze micro-hardness offilm and droplets; test the adhesion base produced film; test the wear under the condition ofnormal temperature in order to do research on the resulting film deposition process. What’smore,people also analyze(bias,deposition temperature,gas reaction pressure,arccurrent,deposition time)the influence on the properties of the film coating process,and hasbeen obtained the best filming technology. Such a research shows that thickness ofthe(Ti,Al)N super-hard ceramic film obtained by multi-arc ion plating technology isgenerally not high (≤3μ m),but the optimizing deposition process makes films have thehigh hardness (HV>1500),the better binding force (>20N,the highest one is40N),and goodwear-resistant performance,which can achieve the requirements of surface film for gearmaterial. In addition,the research results indicate that the properties of the film are not onlyinfluenced by the plating process but also the target components of film. The deposition filmcontains the (Ti,Al)N phase and (Ti2Al)N phase. Because of the film containing differentquantities of Ti,Al elements the film hardness,adhesion strength and wear resistance will bechanged accordingly. Usually with the increase of the Al content, they all increase at thebeginning and then decreased. The changing is caused by the variation of Al content in the film which leads to the crystal structure changing,the preferred orientation changing andlattice distortion. What’s more,the film with optimal value corresponds to the same contentof Al films. In this experimental condition,the film with about50%Al in(Ti,Al)N has thebest comprehensive properties. Including good hardness，good abrasion resistance,and highbonding strength.