Improvement of the Sintering and Mechanical Properties of SiC Utilizing the Increased Milling Efficiency of Si Source Recycled from Si Sludge

抄録

This study enhanced the efficiency in the milling process of preparing SiC powder using the source recycled from Si sludge as a raw material. The sludge, which is formed during machining Si wafer, intrinsically contains SiC (abrasive material), thus due to the high hardness of SiC, the milling effect on the Si sources with sludge was expected to be higher than that of the pure Si. Indeed, the SiC included intrinsically in the sludge resulted in more effective milling of the sludge–carbon mixture; and after high-energy ball milling, the crystallite size of Si in the mixture decreased to 26.8 nm, while the crystallite size of Si in the source without sludge was 49.5 nm. The increase of milling effect in the sludge contributed to the low reaction temperature, improved the sinterability, and reduced the grain size of the sintered SiC. Finally, using the sludge as a raw material, SiC of high density, refined microstructure, and enhanced hardness (H_v: 29.5 GPa, previously reported H_v: (23.7–26) GPa) was obtained. These results suggest that the use of sludge can be an effective way to produce SiC with refined microstructure and enhanced properties, as well as to reduce the cost of production of SiC parts.