Silicon nitride foams from emulsions

摘要

Si_3N_4 foams with open cells were developed by emulsification of an aqueous powder suspension containing an alkane phase (70 vol% of octane or decane), using a surfactant as emulsion stabilizer. 5 wt% of Y_2O_3 and 5 wt% of MgO were used as sintering additives, and the samples were pressureless sintered at 1600 ℃ in N_2. Ceramic foams, mainly based on α-Si_3N_4, with total porosity ranging from ～70 to ～77 vol%, average cell size of ～31 μm for octane and ～55 μm for decane, and compression strength ranging from ～5 to ～20 MPa were produced.