Preliminary Study on Chemical Figuring and Finishing of Sintered SiC Substrate Using Atmospheric Pressure Plasma

Chemical figuring and finishing techniques using atmospheric pressure plasma were proposed for realizing damage free processing of a reaction sintered SiC substrate. Open-air type plasma chemical vaporization machining (PCVM) utilizing He based CF4/O2 mixture process gas demonstrated good linearity of the relationship between removal volume and plasma irradiation time which required in numerically controlled figuring. However, the surface roughness of the substrate processed by PCVM increased with an increase in removal depth by forming pores on the surface because etching rate of residual Si was about 3 times greater than that of SiC.