Effects of mesh-assisted carbon plasma immersion ion implantation on the surface properties of insulating silicon carbide ceramics

Plasma immersion ion implantation (PIII) is an effective materials modification and synthesis technique but has seldom been applied to ceramic materials due to the high electrical resistance that reduces the ion bombardment energy and sometimes causes serious electrical arcing in the instrument. Even in cases where PIII is applicable, the surface properties of the implanted insulating materials can be seriously affected due to the low ion energy and materials damage from electrical arcing. In order to enhance the surface and mechanical properties such as wear resistance of ceramic materials used in many industrial applications, surface modification is needed. In this work, we conduct carbon implantation into sintered α-SiC (silicon carbides that are widely used in vacuum ceramic bearings) using mesh-assisted plasma immersion ion implantation to enhance the surface properties. The use of a conducting grid is necessitated by the high electrical resistance that induces a large voltage drop across the substrate when a negative voltage is applied to the back of the specimen. The rough surfaces make direct assessment of the shallow depth profiles difficult and so we directly measure the hardness and surface friction coefficients, both of which are significantly enhanced after implantation. Our data suggest different wear mechanisms for the unimplanted and implanted samples as inferred from the surface topography and wear tracks.