A new nano-scale rhombic precipitate in the SiC ceramic manufactured by milling-sintering process

A new nano-scale rhombic precipitate was detected in the SiC with 8 wt% Mg additive as obtained by milling and sintering at 1300 degrees C. Transmission electron microscopy (TEM) was employed to characterize the distribution, shape, size, microstructure of the precipitates and to clarify the mechanism of its formation. The results show that the rhombic precipitates are sized under 65 nm and distributed extensively with high density. The rhombic precipitates contain a large amount of Fe derived from the violent collision between the 304 L stainless steel pot and the GCr15 milling balls, and the Fe3Si generated by the reaction between Fe and SiC during sintering. The Fe3Si precipitates and SiC matrix illustrates the (1- 11)Fe3Si//(111)SiC and (11- 1)Fe3Si//(200)SiC orientations. Despite the insignificant strain concentration around the interface between the precipitates and the matrix, the strain values are fairly high for the interface between the precipitates. The nano-scale rhombic precipitates promote the cumulative neighbouring dislocations on the (1-11) (200) and (11-1) planes.

Automated summary

A new nano-scale rhombic precipitate was discovered in SiC with 8 wt% Mg additive. TEM was used to characterize the distribution, shape, size, and microstructure of the precipitates, as well as to determine its formation mechanism. The rhombic precipitates were found to be under 65 nm in size and extensively distributed with high density. They contained a significant amount of Fe from the collision between the stainless steel pot and the milling balls, as well as Fe3Si generated during sintering. The Fe3Si precipitates and SiC matrix exhibited specific crystal orientations.