Ultrasonic Vibration Assisted Mechanical Chemical Polishing (MCP) of Silicon Carbide

Abstract

The mechanical chemical polishing (MCP) process which uses soft abrasives to polish hard workpiece have been employed recently to polish silicon carbide (SiC) ceramic for various applications. An ultrasonic vibration assisted apparatus is designed to investigate the effects of ultrasonic vibration on the efficiency of MCP of SiC by ferric oxide (Fe2O3) abrasives. Experimental results show that the ultrasonic vibration can effectively improve polishing efficiency; the material removal rate is increased by about 60~70%. But it does not lead to a better final surface finish. The effect is more obvious under a higher working pressure condition. It is also found that the output power of ultrasonic transducer is positively correlated with material removal rate. The rise of polishing efficiency is attributed to the increase of local asperities temperatures which promote chemical reaction of silicon carbide with oxygen to form passivation layers. The layers are removed by ferric oxide abrasives afterward.