Preparation and properties of mullite-bonded porous SiC ceramics using porous alumina as oxide

摘要

Mullite-bonded porous silicon carbide ceramics were prepared by an in situ reaction bonding technique and sintering in air with SiC, porous Al_2O_3, and graphite as starting materials. The pores in the ceramics were formed by burning graphite and by stacking particles of SiC and Al_2O_3. The surface of SiC was oxidized to SiO_2 at high temperature. With a further increase in temperature, SiO_2 reacted with Al_2O_3 to form mullite. The reaction-bonding characteristics, phase composition, open porosity, mechanical strength as well as the microstructure of porous SiC ceramics were investigated.