Ca 2+ ‐Doped LaCrO 3 : A Novel Energy‐Saving Material with High Infrared Emissivity

The present study describes the successful synthesis of a Ca 2+ ‐doped LaCrO 3 ceramic with high infrared ( IR ) emissivity, which is important for high‐temperature applications for significant energy saving. It is demonstrated that 20 mol% Ca 2+ ‐doped LaCrO 3 , i.e., La 0.8 Ca 0.2 CrO 3 , exhibited an IR emissivity as high as 0.95 in the spectral region of 3–5 μm, which was 33.8% higher than that of LaCrO 3 . By using La 0.8 Ca 0.2 CrO 3 as IR radiation agent in surface coating of heating unit, the radiative heat transfer could be enhanced significantly. The mechanism of the high IR emissivity of La 0.8 Ca 0.2 CrO 3 was attributed to the following aspects: Ca 2+ doping introduced an impurity energy level of Cr 4+ into LaCrO 3 and increased the hole carrier concentration, enhancing both impurity absorption and hole carrier absorption in the IR region; moreover, the doping caused lattice distortion enhanced the lattice vibration absorption. This novel high IR emissivity ceramic shows a promising future in high‐temperature applications for the purpose of energy‐saving.