DEPOSITION OF TIB2 AT LOW-TEMPERATURE WITH LOW RESIDUAL-STRESS BY A VACUUM-ARC PLASMA SOURCE

Titanium diboride is a very hard, abrasion resistant material that has been identified as having value as a potential erosion resistant material to coat turbine components. It is desired to deposit this coating on materials that, for varying reasons, are adversely affected by the temperatures at which standard physical vapor deposition processes operate. Deposition at lower temperatures in such processes yields a coating with high residual compressive stress. In the present work, titanium diboride has been deposited on various substrate materials by cathodic arc. A technique has been developed, using pulsed high voltage bias applied to the target, that reduces the compressive stress in the coating, even when the coating is deposited at near room temperatures. This pulsed-bias method makes it possible to deposit TiB2 to a thickness of more than 10 mum at near room temperature, making the process suitable for deposition onto temperature sensitive materials.