Influence of Sintering Temperatures on Microstructures and the Thermal Conductivity of CuAlO2 Ceramics

Abstract

Oxide ceramic is a kind of environmental friendly materials, which has attracted more and more interests for its bunch of advantages such as sound chemical, thermal stability, simple synthetic process, cheap price, harmless and safety. Therefore, Oxide ceramic will be a promising material in the future. In this work, polycrystalline samples of CuAlO2 were prepared by a solid state reaction method. The mixture of pure CuO and Al2O3 powders was firstly pressed under the pressure of 60 MPa, and then 200 MPa to prepare pellets of 5 mm thick and 10 mm in diameter. The green compacts were sintered at five different temperatures (1273 K, 1323 K, 1373 K, 1423 K, 1473 K) for various holding times (5 h, 10 h and 15 h) in the air and then the furnace cooled. The crystalline and microstructures of the sintered CuAlO2 bodies were detected by XRD and SEM. The properties of density, thermal conductivity were also investigated in detail. The experimental results show that CuAlO2 bodies were rhombohedral, belonging to R3m space group. It is found that the density and the thermal conductivity of CuAlO2 ceramics were significantly dependent on the sintering temperatures. The density and thermal conductivity increased with increasing the sintering temperatures. The thermal conductivity of samples sintered at 1273 and 1473 K with the same holding time (10 h) were 9.70 and 35.53 W/mk at the room temperature, 3.41 and 8.29 W/mk at 1100 K, respectively.