Mechanical and Thermal Properties of MgAl_2O_4-Y_3Al_5O_(12) Ceramic Composites

摘要

MgAl_2O_4-Y_3Al_5O_(12) ceramic composites were prepared using fused spinel and a Y_2O_3 micropowder as the raw materials. The microstructure and thermal properties of the composites were characterized by X-ray diffraction, scanning electron microscopy, laser flash diffusivity measurements. The mechanical properties were also determined. MgAl_2O_4-Y_3Al_5O_(12) ceramic composites are composed of spinel and garnet structures. The thermal expansion coefficients of MgAl_2O_4 and MgAl_2O_4-Y_3Al_5O_(12) ceramics are similar. The measured thermal diffusivity decreases gradually with increasing temperature. Thermal conductivity of the composites is in the range of 3.3-5.8 W·m~(-1)·K~(-1) from 400°C to 900°C.