Investigation of Zr-ZrN, Zr,Hf -(Zr,Hf)N and Zr,Nb-(Zr,Nb)N coatings deposited on a titanium alloy substrate.

The properties of Zr-ZrN, Zr,Hf-(Zr,Hf)N and Zr,Nb-(Zr,Nb)N coatings deposited on a Ti6Al-4V titanium alloy substrate were studied. It has been established that the introduction of hafnium increases, and niobium reduces the hardness of the coating. The introduction of hafnium also increases, and niobium reduces, the value of the critical fracture load LC2 in the scratch test. It has been established that a layer of nanocrystallites can form at the interface between the substrate and the coating. This layer is presumably formed by particles of an oxide film destroyed during ion etching, spontaneously formed on the surface of the titanium alloy. All samples with coatings have noticeably lower values of the adhesive component of the friction coefficient fadh compared to the uncoated sample at all temperatures. At room temperature, the Zr-ZrN-coated sample has the best fadh value, but when the temperature rises to 500 °C and above, the Zr,Hf-(Zr,Hf)N-coated sample has an obvious advantage.