Preparation and Characterization of High Infrared Emissivity Mn-doped NCO Spinel Composites

NiCr2O4(NCO)spinel composites with different Mn/Ni atomic ratios(Mn/Ni=0.05,0.10,0.15,and 0.20)were synthesized via solid state reaction method.Phase compositions and microstructure of samples were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The TG-DSC curves showed that the appropriate baking temperature for Mn-doped NCO spinel preparation was approximately 1 320℃.X-ray diffraction patterns exhibited the formation of NCO spinel with Fd-3m space group.Valence state of the Mn ions was determined from 2p and 3s X-ray photoelectron spectra.Manganese ions were mostly in divalent and trivalent states,and the ratio of Mn2+/Mn3+was 0.78-0.98.Fourier transform infrared spectroscopy(FTIR)was used to analyze the spectral emissivity of Mn doped NCO spinel.It was revealed that the infrared emissivity of Mn-doped NCO spinel in 1.8-5μm could be significantly enhanced with increasing content of Mn2+,reaching as high as 0.9398.Mn-doped NCO spinel showed excellent radiation performance and good prospect in high emissivity applications in the temperature range of 800-1 200℃.