Internal stress and Young's modulus of TiC coatings

TiC coatings were vacuum deposited onto single-crystal quartz substrates at temperatures ranging from 70 to 4300C. Their Young's modulus and internal stress were measured by the cantilever-electrical capacitance bridge-vibrating reed method during deposition. The measured Young's modulus was approximately 20 X 1011 dyn cm-2. The internal stress was tensile during deposition and decreased slightly with increasing deposition temperature. It ranged between 7.8 and 5.5 X 109 dyn cm-2. Coatings deposited at low temperatures cracked at high thicknesses. This is due to the high internal stress and the low adhesion. The adhesive energy estimated from the crack initiation was about 230 erg cm-2. When the coatings were cooled to room temperature, the stress changed from tensile to compressive because of the bimetallic effect. (Auth.)