Effects of sintering temperatures on the infrared emissivity of La0.7Sr0.3MnO3

► La0.7Sr0.3MnO3 powders were synthesized by the conventional solid state reaction. ► The infrared normal emissivity of La0.7Sr0.3MnO3 powders was studied. ► The resistivity of La0.7Sr0.3MnO3 powders was measured. ► Effects of sintering temperatures on the infrared normal emissivity were discussed. La0.7Sr0.3MnO3 powders were fabricated by the traditional solid state reaction at different temperatures. The crystal structure, infrared transmittance spectra, resistivity and infrared normal emissivity ɛN in the range of 8–14μm were examined using different methods. Effects of sintering temperatures on the infrared emissivity were investigated. It is found that the emissivity of La0.7Sr0.3MnO3 powders decreased first and increased then with the sintering temperature's increase from 1273K to 1523K, and the lowest infrared emissivity was obtained when calcined at 1473K. The trend of the variation of the infrared normal emissivity with sintering temperature's increase was opposite to that of crystallite size and similar to that of resistivity.