Elimination of grain boundaries and its effect on the properties of silicon nitride ceramics. Issue 8 (1st June 2020)

• Record Type: Journal Article
• Authors: Hu, Feng; Zhu, Tianbin; Xie, Zhipeng; Liu, Jian; Hu, Zunlan; An, Di
• Is Part Of: Ceramics international. Volume 46:Issue 8(2020)Part B
• Page Start: 12606
• Page End: 12612
• Publication Date: 2020-06-01
• Subjects: Silicon nitride ceramics -- Thermal conductivity -- Grain boundary -- Post-sintering heat treatment; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.02.024
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: To eliminate the excess grain boundary phase in silicon nitride ceramics prepared through hot pressing and a post-sintering heat treatment, carbon was introduced into the sintered ceramics. This was accomplished in two ways: first, a small amount of carbon was used as a sintering additive; however, this creates large pores in the ceramics, resulting in a decrease in the thermal conductivity and mechanical properties of the samples. Alternatively, the C/Si3 N4 power bed could be used instead of the BN/Si3 N4 power bed, which obviously eliminates the grain boundary phase. Further, the C/Si3 N4 power bed possess excellent mechanical properties while increasing the thermal conductivity of the samples. Therefore, the silicon nitride ceramics with 123 W m −1 K −1 thermal conductivity and 986 MPa bending strength of can be obtained using the C/Si3 N4 powder bed during the post-sintering heat treatment.