LaMAl11O19 (M = Mg, Fe) ceramic coatings were plasma-sprayed on nickel-based superalloy with NiCoCr-AlYTa as the bond coat. The microstructure, thermal shock resistance and thermal emissivity of these two ceramic coatings were investigated. LaMAl11O19 coatings exhibit a characteristic of stacked lamellae, and consist mainly of a magnetoplumbite-type hexaaluminate phase and an amorphous phase. During thermal cycling, the amorphous phase disappears and a LaAlO3 phase is formed at temperatures of both 1000 and 1200 degrees C. The thermal cycling numbers of LaMgAl11O19 coating are 102 at 1000 degrees C and 42 at 1200 degrees C; LaFeAl11O19 has a thermal cycling lifetime of 87 at 1000 degrees C and 30 at 1200 degrees C, respectively. Normal spectral emissivity of nickel-based superalloy is about 0.2 over the whole wavelength range of 3-14 mu m. However, the emissivity of LaFeAl11O19 coating is about 0.7 at short wavelengths and above 0.9 in the wavelength range of 7-14 mu m. (C) 2013 Elsevier B. V. All rights reserved.