Hot-spots generation, exaggerated grain growth and mechanical performance of silicon carbide bulks consolidated by flash spark plasma sintering

Abstract

Flash Spark Plasma Sintering (FSPS) that combines flash sintering and electric field assisted sintering was used to densify SiC ceramics. FSPS was compared with ‘conventional’ SPS which used a moderate 100 °C·min−1 heating rates. Dense SiC specimens were obtained despite being at temperature of 1850–2050 °C for few seconds. FSPS lead to generation of hot-spots and thus caused localized exaggerated grain-growth. This allows producing silicon carbide ceramics with bimodal grain size distribution. Analysis of microstructure and strength of silicon carbide ceramics consolidated using flash heating allowed proposing several optimization routes of the FSPS process.