Microstructure, corrosion and tribological properties of Ti(CN) multilayer coatings on 35CrMo steel by CVD

Multilayer hard coatings of TiC/Ti(C,N)/TiN on 35CrMo steel substrates were deposited by a chemical vapor deposition system (CVD). X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDX) were used to analyze phase composition, morphology, and chemical composition of the coatings. The mechanical, corrosion, and wear properties of the produced coatings were primarily examined. The results indicate that multilayer coatings are consisted of TiC, Ti(C0.2N0.8), and TiN. The coatings surface is dense, and the thickness is about 11 mu m. The adhesion between coatings and steel substrate was characterized by critical load (L-c) and is found to be about 70 N. The microhardness of the multilayer coatings is HV 2400, which is about 5 times as that of the 35CrMo steel substrate. The corrosion current of the coated sample is 4.368 x 10(-5) A center dot cm(-2), which decreases by one order of magnitude compared with the uncoated one (1.324 x 10(-4) A center dot cm(-2)). Friction and wear tests show that the TiC/Ti(C,N)/TiN coatings with high hardness adhere well to the 35CrMo substrate and display good wear resistance and low friction coefficient under non-lubricated friction test at room temperature.