Abstracts Selected from Naihuo Cailiao(Refractories)--A Bimonthly in Chinese

摘要

Preparation of Si_(3)N_(4)porous ceramics via foam-gelcasting combined catalytic nitridation/Han Lei,Li Xiaojian,Zhang Haijun//Naihuo Cailiao.-2021,55(5):395Abstract:Si_(3)N_(4)porous ceramics were fabricated by foam-gelcasting combined catalytic nitridation using high-purity silicon powders as the starting material and Fe(N_(3))_(3)·9H_(2)O as the catalyst and CTAB as the foaming agent.The effects of the nitriding temperature(1200,1250,1300 and 1350℃)and the catalyst addition(0,1%,3%and 5%,by mass)on the phase composition,microstructure and physical properties of the Si_(3)N_(4)porous ceramics were investigated.The results show that with 1%of Fe(N_(3))_(3)·9H_(2)O,the Si_(3)N_(4)porous specimen nitridized at 1300°C has 29.7 MPa of compressive strength and 55.1%of apparent porosity.The relatively high strength of the porous ceramics can be attributed to the highly catalytic effect of Fe(N_(3))_(3)·9H_(2)O,which promotes the growth of Si_(3)N_(4)whiskers inside the specimen and plays a positive role in the improvement of mechanical properties.