Abstract
LaMAl11O19 (M=Mg, Fe) ceramic coatings were plasma-sprayed on nickel-based superalloy with NiCoCrAlYTa 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°C. The thermal cycling numbers of LaMgAl11O19 coating are 102 at 1000°C and 42 at 1200°C; LaFeAl11O19 has a thermal cycling lifetime of 87 at 1000°C and 30 at 1200°C, respectively. Normal spectral emissivity of nickel-based superalloy is about 0.2 over the whole wavelength range of 3–14μm. However, the emissivity of LaFeAl11O19 coating is about 0.7 at short wavelengths and above 0.9 in the wavelength range of 7–14μm.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.