Preparation of environmentally friendly high‐emissivity Ca2+‐Fe3+ co‐doped LaAlO3 ceramic

Abstract

AbstractCa2+‐Cr3+ co‐doped LaAlO3 is an excellent ceramic material with high emissivity; however, it is harmful to the environment because of the presence of Cr3+ ions. In this study, Ca2+‐Fe3+ co‐doped LaAlO3 ceramic materials were successfully prepared via a high‐temperature solid‐state reaction. The emissivity of Ca2+‐Fe3+ co‐doped LaAlO3 was 0.91, which is approximately equal to that of Ca2+‐Cr3+ co‐doped LaAlO3. To compensate for the lack of data on the thermophysical properties of doped LaAlO3 high‐emissivity ceramics, the thermal expansion coefficients and thermal conductivities of LaAlO3 doped with Ca2+‐Fe3+ or Ca2+‐Cr3+ were investigated. The thermal conductivities of La0.9Ca0.1Al0.9Fe0.1O3 and La0.9Ca0.1Al0.9Cr0.1O3 at 1200°C were 3.802 and 3.707 W·m−1·K−1, respectively. The thermal expansion coefficients of La0.9Ca0.1Al0.9Fe0.1O3 and La0.9Ca0.1Al0.9Cr0.1O3 at 1200°C were 11.49×10−6 and 11.41×10−6 K−1, respectively. These results indicate that Ca2+‐Fe3+ co‐doped LaAlO3 exhibits great potential as a new generation of environmentally friendly near‐infrared radiating materials in the field of energy efficiency.