Synthesis and Friction Behavior of Chemically Vapor Deposited Composite Coatings Containing Discrete TiN and MoS 2 Phases

Composite coatings containing discrete crystalline phases of TiN and MoS 2 were deposited on Si, graphite, and Ti‐6A‐14V alloy substrates by simultaneous chemical vapor deposition. MoF 6 and H 2 S were utilized as the precursors for MoS 2 formation, while Ti((CH 3 ) 2 N) 4 and NH 3 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 MoS 2 in the composite microstructure could be controlled by adjusting the MoF 6 concentration in the reagent mixture. Encouraging friction and wear characteristics against silicon nitride were obtained for a composite coating which was rich in MoS 2 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.