Pressureless solid-state sintering of SiC ceramics with BN and C additives

Journal of Asian Ceramic Societies

Young-Wook Kim¹  Rohit Malik¹ 

[1] Functional Ceramics Laboratory, Department of Materials Science and Engineering, The University of Seoul, Seoul, Republic of Kore;

关键词: SiC;    pressureless solid-state sintering;    electrical conductivity;    thermal conductivity;    mechanical properties;   

DOI  :  10.1080/21870764.2021.1946268

来源: Taylor & Francis

【 摘 要 】

This study proposes BN as a new sintering aid for pressureless solid-state sintering of SiC ceramics. The full densification of SiC ceramics for 0.5–2.7 wt% BN addition showed the composition tolerance of the newly developed ceramics. The electrical resistivity decreased by an order of magnitude (107→106 Ω·cm) as BN content increased from ~0.5 to ~0.9 wt% because of the increased BN-derived B doping in the SiC lattice. A further increase in BN content had no significant effect on the electrical resistivity, which is attributed to the limited solubility of B in the SiC lattice. The thermal conductivity decreased with increasing BN content owing to increased phonon scattering at B-doped sites and the thermally insulating BN phase located at the grain boundaries. The fracture toughness increased with increasing BN content owing to interfacial debonding at the weak SiC-BN interfaces. However, intrinsically weak BN grains with low hardness were responsible for reduced flexural strength and hardness with increasing BN content.

【 授权许可】

CC BY