Enhanced thermal radiation blocking and high temperature stability of nanostructured YSZ thermal barrier coatings through carbon film coating
Liuchao zhang, Fa Luo, Yingying Zhou, Yaru Cao, Junjie Yang, Yuqin Li, Yuchang Qing
Abstract
The semi-transparency to thermal radiation, coupled with the low nanoparticle retention and formation of semi-melted particles during plasma spraying, significantly limit the high temperature application of nano-YSZ thermal barrier coatings. To deal with these challenges, this study introduces an innovative approach that involves coating nanoparticles with carbon film to prevent them from melting and merging during plasma spraying process. This method substantially increases the nanoparticle content within the coating, and nano pores formed at the nanoparticle surfaces when carbon film was removed at 800 °C. These nano-pores, in combination with nanoparticles, enhance thermal radiation scattering, improving the scattering coefficients and thermal radiation blocking capability of coating. In contrast to conventional YSZ TBCs, the simulated temperature of substrate under service condition drops by up to 26.26 K due to decreased radiative heat transfer, and by 111.2 K when considering reduced thermal conductivity. Additionally, the scattering coefficients remains stable within 1-5 μm range even after heat treatment at 1300 °C for 100 hours, as the coarsened nanoparticles size approaches the wavelength of thermal radiation. Thus, nano-YSZ TBCs with enhanced thermal radiation blocking and high temperature stability can be created by this approach for higher temperature application.