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Mechanical transmission, gear failure accounted for most of the failure of the total, the gear is subjected to bending stress in the course of transmission, contact stress, impact force the combined effects of a variety of forces, various forms generated VALID. Traditional surface hardening process (overall quenching, surface hardening, nitriding, etc.) gradually can not meet the needs of the industrial production of new surface hardening technology (PVD, CVD) is being more and more attention. In this paper the use of multi-arc ion plating technique commonly used gear steel 40Cr surface preparation TiAlN / TiN film, different process parameters on the surface morphology of the film, the internal organizational structure, microhardness, oxidation resistance and friction and wear properties . A target prepared TiAlN / TiN film used as a purity of 99.99% pure aluminum target and industrial grade titanium target, the coating parameters for matrix 0 ~~ 500V negative bias, a titanium target current 60A, the aluminum target current 40 to 80A, N 2 partial pressure of 0.3 ~ 1.3Pa, deposition temperature of 200 ° C, the plating system time 90 min. The results show that: the substrate negative bias have a great impact on film performance, too high or too low substrate bias makes the film uneven surface, lower surface hardness. Matrix the higher the negative bias, the layer of Ti, Al atom content is lower; target current on the film performance has a significant impact, the more uneven the surface of the current the higher layer. Reduce microhardness rise with increasing target current. The higher the current, the layer of Ti, Al atom content the higher; N 2 partial pressure is increased to improve the film surface morphology from a beneficial effect, but the high N 2 partial pressure will result in a \The oxidation resistance of TiAlN / TiN film to be much better than 40Cr substrate and TiN film. In a 200 ° C air environment, 40Cr substrate surface appears very obvious traces oxidation. Temperature to 700 ° C, the surface oxide generated significantly thickening and cracking off, completely unable to protect the substrate. TiN film shows the oxidation resistance in a 200 ° C air environment is better, but, to 700 ℃, TiN film is completely oxidized, and the color changed from the original golden yellow to brown and surface peeling, to expose the substrate. TiAlN / TiN film either 200 ℃ or 700 ℃ environment showed excellent antioxidant properties, the film is complete, no cracking, no peeling. The main test parameters on friction and wear properties of Research TiAlN / TiN film in dry rotary sliding conditions: normal load of 10 ~ 30N, line speed 13188mm/min, duration 10min. By contrast 40Cr the test results under the same conditions, we found that the friction coefficient and the wear amount of the TiAIN / TiN film should be significantly lower than the 40Cr. Meanwhile, we also found a downward trend with the normal load increases the friction coefficient of the film.
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