The Effect of Powder Oxygen Content on the Morphology of Silicon Carbide Densified Via Spark Plasma Sintering

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

“…Previous studies have shown that the addition of sintering aids could successfully enhance the sinterability of SiC ceramics at the relatively lower sintering temperature, either through solid phase sintering 9,10 or liquid phase sintering 11,12 . The oxygen content on the surface of SiC particles has been proven to play a critical role in both sintering mechanisms, especially during pressureless sintering, 13,14 as the SiO 2 layer on the surfaces of SiC powders can inhibit densification. At a temperature above 1800°C, SiC would react with SiO 2 , resulting in the release of SiO and CO and the residual porosity, according to the following reaction 15 : $$$$\begin{equation}2{\mathrm{Si}}{{\mathrm{O}}_2}\left( {\mathrm{s}} \right) + {\mathrm{SiC}}\left( {\mathrm{s}} \right) \to {\mathrm{3SiO}}\left( {\mathrm{g}} \right) + {\mathrm{CO}}\left( {\mathrm{g}} \right)\end{equation}$$$$…”