THE MECHANICAL, TRIBOLOGICAL AND OPTICAL-PROPERTIES OF TI-C-H COATINGS, PREPARED BY DC MAGNETRON SPUTTERING

The aim of this work was to determine the correlations between the gro wth parameters of diamond-like coatings with small amount of titanium (from 10 to 20 at.%) prepared by d.c. magnetron sputtering of the Ti t arget in a CH4 + Ar gas mixture and their mechanical, tribological and optical properties. The composition, microhardness, internal stress; friction coefficient, adhesion and optical properties (E-g, n, k) depe ndent on methane flaw rate, substrate bias and interlayer formation we re studied. It was found that the optical properties of Ti-C:H films ( E-g, n, k) monotonically approach those for C:H films when the titaniu m concentration is decreased. This enables us to consider Ti-C:H film as a-C:H film With TIC inclusions, when the Ti concentration is low. A n increase in the negative substrate bias voltage to -100 V leads to a considerable increase in layer microhardness, with a slight decrease at a further bias increase to -200 V. The internal stresses are decrea sed under the same conditions due to the substrate temperature growth. The best coatings had friction coefficients 0.12-0.15, microhardness 14-18 kN/mm(2) and demonstrated elastic behaviour and good adhesion. T he nature and correlation of these properties are discussed. (C) 1998 Elsevier Science S.A.