The Study Of Microstructure And Properties Of The Prepared Ti₂AlN Ternary Compounds Ceramic Films

In the Ti-Al-N coating system, there is a kind of significant ternary compound Ti2AlN belonging to Mn+1AXn (N=1,2,3) with the advantages of both metals and ceramics. Under the room temperature, it has some metal properties such as low hardness, good workability, good thermal conductivity and electrical conductivity. And it also has the ceramic features, such as superior elasticity modulus, good corrosion resistance and high temperature oxidation resistance and so on. Because of the lack of the research of Ti2AlN thin-film material, it is valuable to do this research. This research will put how to synthetic the high-purity Ti2AlN thin-film material as the key.In this paper, by using the multi arc ion plating technology precipitating Ti-Al-N thin film on the stainless steel substrate06Cr19M10and taking the subsequent annealing treatment to the Ti-Al-N deposition film, the Ti2AlN ternary compound film will be worked out. At the same time, we optimized its preparation technology by the orthogonal experiment design method. Then research is mainly focused on that the multi arc ion plating deposition technology and annealing technology has influence to the thin film composition, surface morphology and phase composition of the thin film. And we take the test and analysis to the decay resistance and high temperature oxidation resistance of Ti2AlN thin film.The result of the research shows under the situation like alloy target current75A, negative bias400V, duty ration90%, nitrogen flux40sccm, the Ti-Al-N thin film has the best comprehensive performance.After the annealing process taking the test and analysis to deposition film with the XRD phase analysis, we found that there appeared Ti2AlN in coating films when the situation is nitrogen flux40sccm, annealing temperature700℃.According to the comparison to different annealing temperatures and the film hardness and friction coefficient before annealing and after, we found that with the increasing temperature, the hardness and friction coefficient both decreased. And it is particularly obvious to phase coating reduction of the formation of Ti2AlN. This is mainly because the hardness of Ti2AlN is low and it has layered structure and self-lubrication. Its hardness is averagely decreased by54.1%before annealing and its friction coefficient is averagely decreased by39.4%.Polarization curve and ac impedance test result shows that Ti2AlN thin film with the same process has better corrosion resistance than TiN film. The increasing weight per unit area of the sample after heating and constant temperature oxidation test shows that Ti2AlN thin film has better high temperature oxidation resistance than TiN film. The oxidation mechanism of thin film is that Al2O3oxidation layer of protective film which Al atom compound into by diffusing to the surface can play a protective role to the oxidation film/nitride film. Consequently it can prevent further oxidation for the nitride film.