Thickness effects on the sinterability, microstructure, and nanohardness of SiC-based ceramics consolidated by spark plasma sintering

This study aimed to investigate the effects of the original thickness on the densification, microstructure, and nanoindentation hardness of silicon carbide (SiC) ceramics prepared by the spark plasma sintering (SPS) process. The densification of SiC ceramics with different initial thicknesses ranging from 50 to 2000 mu m was investigated in combination with varying SPS sintering temperature at 1700-1900 degrees C. The results indicated that the densification of SiC sample with the initial thickness of 50 mu m was complete after sintering at 1700 degrees C. On the contrary, when the initial thickness exceeded 50 mu m, it resulted in a porous microstructure. When the initial thickness varied from 50 to 100 mu m, dense SiC monolithic could be obtained after sintering at 1800 degrees C. All the samples were fully densified after sintering at 1900 degrees C. The predominant factors for the thickness effect were mainly derived from the unique characteristics of SPS. The hardness of SiC ceramics was measured using nanoindentation, and it was found to have a strong correlation with the initial thickness, mainly attributed to the densification status. The dense SiC product demonstrated nanoindentation hardness with high values of similar to 28.0 GPa.

Automated summary

This study investigated the effects of the initial thickness on the densification, microstructure, and nanoindentation hardness of SiC ceramics prepared by the spark plasma sintering process. The results showed that the initial thickness played a significant role in the densification and hardness of the materials.