Synthesis and infrared emissivities of Mn-doped ZnO:Co powders

Zn0.97Co0.03O, Zn0.94Mn0.03Co0.03O, and Zn0.92Mn0.05Co0.03O powders were synthesized by solid-state reaction at various temperatures. The structure characterizations of as-prepared samples were measured by XRD. The resistivities of the samples were measured using four probe method. The infrared emissivities at the wavelength of 8-14 μm were investigated by an infrared emissivity measuring instrument. The results indicate that the peaks arising from ZnMnO3 are observed. As the temperature rises, these peaks weaken and disappear, meanwhile, the infrared emissivity decreases first and then increases. ZnO:Co with lower Mn concentrations shows lower emissivities. Sintering temperature and doping concentration have similar effects on infrared emissivity and resistivity. With the formation of ZnMnO3, the emissivities of Mn-doped ZnO:Co are not as high as those of ZnO:Co below 1200 °C.