Effect of Mg doping on the infrared emissivity of ZnO powders at high temperature

Infrared emissivity of semiconductor material determines infrared radiation capability of semiconductor material. In recent years, researchers have focused on the infrared emissivity performance of ZnO at room temperature. The infrared emissivity performance of ZnO at high temperatures is rarely studied. In this paper, Zn1-xMgxO powders were prepared by sol-gel method. The infrared emissivity of powders with different x (x = 0, 0.01, 0.03, 0.05, 0.07) were investigated from room temperature to 800 °C. The composition and calcination temperature of precursors were determined by DSC, and the changes in morphology, particle size, microstructure and phase compositions were studied by SEM, EDS and XRD separately. The changes of infrared emissivity of powders with different Mg doping concentrates from room temperature to 800 °C are explained by dielectric mechanism, conduction mechanism and lattice vibration mechanism, and the varies of infrared emissivity with temperature, which showing a U-shaped curve are also explained by the three mechanisms mentioned above. An effective and convenient method for regulating the infrared emissivity of ZnO is provided in this paper.