Microstructures and properties of solid-state-sintered silicon carbide membrane supports

Abstract Porous solid-state-sintered SiC (S–SiC) membrane supports were successfully fabricated by pressureless sintering at 2150 °C in argon, using fine and coarse graded SiC powders as the main starting material. There were uniformly distributed and fully interconnected pores in as-acquired S–SiC membrane supports, accompanied with similar apparent porosities for all of them. When increasing the size of coarse SiC powder, their average pore sizes were distinctly enlarged from ∼1.6 μm to ∼2.3 μm, which significantly enhanced their nitrogen permeability from 0.9 × 10−13 m2 to 2.6 × 10−13 m2. Moreover, S–SiC membrane supports possessed outstanding flexure strengths of 134.1 ± 21.3 MPa at room temperature and 88.7 ± 8.4 MPa at 1000 °C owing to strong interface bonding between SiC grains. Compared with the traditional SiO2 -bonded and mullite-bonded SiC supports, S–SiC membrane supports presented their great superiority in high-temperature flexure strength as well as acid and alkali corrosion resistance, which permitted them to be potentially applied in high-temperature and strongly corrosive environments.