Synthesis and Friction Behavior of Chemically Vapor Deposited Composite Coatings Containing Discrete TiN and MoS2 Phases

Composite coatings containing discrete crystalline phases of TiN and MoS2 were deposited on Si, graphite, and Ti‐6A‐14V alloy substrates by simultaneous chemical vapor deposition. MoF6 and H2S were utilized as the precursors for MoS2 formation, while Ti((CH3)2N)4 and NH3 were used for TiN deposition. The composition and microstructure of the coatings were investigated by X‐ray diffraction, Auger electron spectroscopy, and transmission electron microscopy. The molar ratios of TiN and MoS2 in the composite microstructure could be controlled by adjusting the MoF6concentration in the reagent mixture. Encouraging friction and wear characteristics against silicon nitride were obtained for a composite coating which was rich in MoS2 at the coating surface, with TiN as the major phase near the substrate interface. Friction coefficients at room temperature in air were typically in the range of 0.07 to 0.3. The friction coefficients remained comparable at 573 K, but increased to 0.7 to 1.0 at 673 K. A friction coefficient value of −0.3 was, however, obtained from a composite coating tested at 973 K.