Dual-band Infrared Radiation Performance of Spinel-type Fe₂O₃-CuO-MnO₂ Ceramic Powder at Room Temperature

The effect of molar ratio and dopant on two-band infrared radiation performance of Fe₂O₃-CuO-MnO₂ transition metal oxide materials were studied. Infrared emissivities of the materials at 3–5 μm and 8–14 μm bands were detected by using IRE-2 dual-band emissivity instrument at room temperature. UV-VIS absorption spectra of the materials were studied by using ultraviolet-visible spectrophotometer. Subsequently, width of the forbidden gap was calculated by using the Tauc plot method. The phase evolution and microstructure were analyzed by using XRD and SEM-EDS. It is found that the emissivity of the Fe₂O₃-CuO-MnO₂ spinel infrared materials at 8–14 μm band is much higher than that in 3–5 μm band. Lattice distortion of the spinel crystals was observed and the width of forbidden gap was decreased with increasing content of Fe₂O₃. The presence of Cr₂O₃ and rare earth oxides Eu₂O₃ and Y₂O₃ is beneficial for improving the infrared emissivity in 3–5 μm band. The width of forbidden band is obviously reduced and the optimal infrared radiation in 3–5 μm band was obtained when Y₂O₃ was introduced, where the value of emissivity was increased by 22.3% to 0.890. Furthermore, Cr₂O₃ played a stronger role in improving the infrared radiation in 8–14 μm band, while the emissivity was increased from 0.909 to 0.956.