In-situ preparation of SiC reinforced Si3N4 ceramics aerogels by foam-gelcasting method. Issue 1 (1st January 2022)

• Record Type: Journal Article
• Authors: Han, Lei; Li, Xiaojian; Li, Faliang; Zhang, Haijun; Liu, Xueyin; Li, Guangqiang; Jia, Quanli; Zhang, Shaowei
• Is Part Of: Ceramics international. Volume 48:Issue 1(2022)
• Page Start: 1166
• Page End: 1172
• Publication Date: 2022-01-01
• Subjects: SiC reinforced Si3N4 ceramics aerogels -- Foam-gelcasting -- Catalytic reaction -- Low thermal conductivity; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.09.201
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: High strength SiC reinforced Si3 N4 ceramics aerogels (SCSNCAs) were fabricated via foam-gelcasting and subsequent catalytic reaction, utilizing industrial Si and melamine as raw materials, a small amount of incidental Fe impurities in Si powder as the catalyst and cetyltrimethylammonium bromide (CTAB, the amount of 0.075 wt%) as foaming agent. The effects of solid loading level and reaction temperature on phase composition, microstructure and mechanical properties of the as-prepared SCSNCAs were examined. The aerogels prepared at 1423 K using a slurry of solid loading level of 30 wt% (Si:melamine = 3:1, mass ratio) had porosity of 91.9%, having compressive and specific strength of 0.8 MPa and 3.8 MPa·cm 3 ·g −1 exhibited the lowest thermal conductivity of 0.066 W/(m·K) at 473 K. Compared with the control sample (without melamine, i.e., Si3 N4 aerogels without the formation of SiC), the specific strength of the SCSNCAs increased by about 10%, which was attributed to the additional reinforcement from SiC whiskers formed in the Si3 N4 matrix of the aerogels.