The high emissivity coatings with different surface roughness using iron oxide, silicon carbide and cobalt
oxide as high emissivity fillers were fabricated by controlling the spray times and the solid loading of coating slurry.
The room-temperature emissivity of the high emissivity coatings with different surface roughness was measured by
AE radiometer,and the high-temperature emissivity at 800℃ was determined according to GB/ T 7287—2008. The
images of the high emissivity coatings were characterized by scanning electronic microscopy and optical microscopy,
and the surface roughness of the high emissivity coatings was measured by scanning probe microscopy. It is found that
the room-temperature emissivity of the high emissivity coatings had a change of 0. 02 to 0. 05 in the condition of radiative
heat transfer during the surface roughness of the high emissivity coatings changing from 2. 75 μm to 225. 70 μm,
while the high-temperature emissivity of the high emissivity coatings had no change in the condition of heat conduction
during the surface roughness of the high emissivity coatings changing from 2. 75 μm to 36. 99 μm.