Pore Structure and Mechanical Property of Porous Materials Prepared by Direct Sintering of Silicon Slag and Glass Powder

Porous materials were prepared by the powder direct sintering method with silicon slag and glass powder as raw materials. The effect of sintering temperature (700-900℃), sintering time (15-120 min) and heating rate (10-100℃·min^-1) on the apparent density, porosity, phase composition and compressive strength of the porous materials was investigated. The results show that the uniformity of pore structure deteriorated with the increase of sintering temperature. The apparent density decreased first and then increased with the increase of sintering temperature, increased with the extension of sintering time and decreased with the increase of heating rate. The variation of porosity was opposite to that of apparent density. The main phases of porous materials included glass phase and crystalline phases of Si, SiC, SiO₂ and Ca₂Al₂SiO₇, and the crystallinity decreased with the increase of sintering temperature. The compressive strength increased and then decreased with increasing sintering temperature. When the powder mixture was sintered at 750℃ for 30 min with heating rate of 30℃·min^-1, the obtained porous material had main crystalline phases of Si and Ca₂Al₂SiO₇, the maximum compressive strength of 1.60 MPa, the apparent density of 0.43 g·cm^-3 and the porosity of 80%.