The mechanical and tribological properties of magnetron sputtered Ti-C:H coatings

The aim of this work is to determine a correlation between the growth parameters of diamond-like coatings with small amounts of titanium (from 10 to 20 at.%) prepared by DC magnetron sputtering of a titanium target in CH4 + Ar gas mixture and their mechanical and tribological properties. The composition, microhardness, internal stress, friction coefficient and adhesion, the evaluation of substrate temperature dependence on methane flow rate, substrate bias and interlayers formation were evaluated. It was found that an increase in the negative substrate bias voltage to -100 V leads to a considerable increase in the layers' microhardness, which slightly decreases with a further bias increase to -200 V. The internal stresses decreased at the same conditions due to substrate temperature growth. The best coatings had a friction coefficient of 0.12-0.15, a microhardness of 13-15 kN/mm(2) and demonstrated elastic behaviour and good adhesion. The nature and correlation of these properties are discussed. (C) 1998 Elsevier Science S.A.