Sintered glass-ceramic matrix composites made from Latvian silicate wastes

Powder technology and sintering were used to fabricate glass-ceramic matrix composites from Latvian industrial wastes and alumina platelets reinforcement. The optimization of the sintering behaviour of glass-ceramic compositions containing clay and alumina platelets was carried out. Highly crystalline and dense products (> 90% theoretical density) were fabricated by sintering at temperatures in the range 1040 to 1060°C, depending on composition. Addition of waste glass to influence the sintering temperature and sintering interval was also investigated. Composites showed higher fracture strength (up to 97 MPa) and hardness than unreinforced glass-ceramics. The best composition in terms of density and mechanical properties contained 20 wt% alumina platelets. The matrix exhibited a microstructure composed mainly of elongated crystals of pyroxene type in a residual glassy matrix. These composites are candidates for applications as building materials, such as floor and wall tiles, and for manufacturing machine elements and parts.