Effect of Al2O3 on thermal properties of 0.5CaAl2Si2O8–0.5CaMgSi2O6 glass–ceramics

Abstract The thermal properties of 0.5CaAl 2 Si 2 O 8 –0.5CaMgSi 2 O 6 glass–ceramics with Al 2 O 3 were investigated as a function of Al 2 O 3 volume fraction (V f ). With increasing of Al 2 O 3 content, the anorthite (CaAl 2 Si 2 O 8 ) phase was increased up to 0.08 V f of Al 2 O 3 and then decreased, while the diopside (CaMgSi 2 O 6 ) phase was not changed remarkably. The coefficient of thermal expansion (CTE) of the sintered specimens was dependent on the degree of crystallization of glasses. The thermal conductivity of the sintered specimens was affected by the thermal diffusivity and density rather than the specific heat capacity ( C p ). The thermal conductivity of 0.5CaAl 2 Si 2 O 8 –0.5CaMgSi 2 O 6 glass–ceramics was increased and the CTE was decreased with the addition of Al 2 O 3 .