Infrared emissivity of Co, Ni Co-doped ZnO powders by solid-state reaction

This paper studies the infrared emissivity of Zn_0.99-xNi_0.01Co_xO (x=0.00, 0.01, 0.03, 0.05) powders prepared by solid-state reaction. The phase and morphology of samples were characterized by XRD and SEM. The UV absorption spectra and infrared emissivity at the wavelength of 8-14μm were measured by UV Spectrophotometer and IR-2 Dual-Band Emissivity Measuring Instrument. The peak of the impurity phase, NiO, is detected at temperatures below 1150°C. The optical band-gap decreases with increasing Co concentration and calcination temperature, which are much smaller than results in other studies. The infrared emissivity of Zn_0.99-xNi_0.01Co_xO falls with the increase of Co content. It descends to the minimum (0.772) at 1100°C and then ascends when the temperature is raised.