Effect Of The Mo Target Current On Microstructure And Mechanical Properties Of CrMoAlN Coatings

Mold always fail from the surface because of the poor working environment.Through the surface modification of PVD can greatly improve the service life of mold.We deposited CrMoAlN coating on the surface of Cr12 cold working die steel by closed field unbalanced magnetron sputter ion plating in this paper.The effects of the different Mo target current on the structure and properties of the coating were also studied.The films'microstructure was investigated by SEM and XRD.The chemical composition was analyzed by XPS and EDS.The hardness of coating and the adhesion strength of coating-substrate were measured by nano indentation tester and Rockwell indentation test respectively.The wear resistance and high temperature oxidation resistance of the coating were tested by the friction and wear testing machine and the high temperature box type resistance furnace.The research showed that with the increase of Mo content in the Cr Al N coatings,the size of grain becomes smaller.The high temperature oxidation experiments indicated that the three kinds of coating with different Mo content exhibited good high temperature oxidation resistance before 450?and still maintained a good adhesion ability at 650?.But the crack distribution was much more intensive at 850?,so CrMoAlN coating is not applicable to the working environment which has a high temperature above 850?.Friction and wear experiments showed that the wear characteristics of Mo containing coating increased gradually with the Mo content increase under the experimental temperature below 300?because of the lubrication function of Mo O₃ which was produced in the process of wear test.