上海科技大学知识管理系统

In the traditional porous reaction-bonded silicon carbide (RBSC) ceramic, the phenomenon of residual silicon usually happens due to the usage of monatomic silicon as reactant, which greatly weakens its high-temperature properties, as well as corrosion resistance. In this paper, Si3N4 was successfully utilized as silicon source for the preparation of porous RBSC ceramics. Only SiC phase in the final bulks was detected by X-ray, indicating the achievement of avoiding residual silicon. There were homogeneous and isotropous pores with 48.3% of porosity for as-acquired RBSC ceramic. Its average pore size was similar to 1.6 mu m, while the pore throat size was less than 1 mu m. Compared with porous oxide-bonded SiC ceramic, porous RBSC ceramic showed superiority in N-2 permeability (217 m(3)/(m(2). h.bar)), as well as flexural strength at normal temperature (35.5 +/- 2.3 MPa), and high temperature of 1000 degrees C (21.2 +/- 1.7 MPa). Moreover, porous RBSC could keep intact after exposing in boiling solutions of 10 wt% H2SO4 and 1 wt% NaOH for 12 h, indicating its chemical stability in the acid and alkaline environment. (C) 2020 Elsevier Ltd. All rights reserved.