Wear resistant TiMoN coatings deposited by magnetron sputtering

TiMoN coatings with different Mo concentrations were deposited using a reactive magnetron sputtering technique and characterized by X-ray diffraction, nano-indentation, pin-on-disc testing, SEM/EDS and X-ray photoelectron spectroscopy. Mo alloying of TiN coatings generally enhances hardness. When tested in a pin-on-disc test against WC–Co pin, the coefficients of friction of TiMoN coatings were found to decrease with the increase in Mo atomic fraction, with the lowest values (0.4–0.5) being only one-half that of TiN coating (1.03). The underlying mechanism of the Mo effect is the formation of lubricious MoO3 on the wear track. The combination of low coefficient of friction and enhanced hardness reduces the wear rate of TiMoN coatings to less than 2.5% of the wear rate of TiN coating.