Carbon nanotubes doped SiO2/SiO2–PbO double layer high emissivity coating

Abstract Carbon nanotubes (CNTs) doped SiO 2 /SiO 2 –PbO double layer coating is prepared on Ni alloy plate by hybrid SiO 2 sol-gel method and SiO 2 –PbO powders with certain heat treatment. The SiO 2 –PbO top layer is observed to possess a kind of porous and skeleton-like structure. The emissivity enhancement mechanisms of the coating's structure and doping carbon nanotubes are investigated in this study. Spectral emissivity measurements from 1.28 to 25 μm at 570 and 820 K show that the carbon nanotubes doped SiO 2 /SiO 2 –PbO double layer coating possesses strong blackbody character and the coating's emissivity can reach as high as 0.94 at 820 K.