High-emissivity coatings and applications

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High-emissivity coatings can absorb not only the radiative heat emitted but also the convective heat emitted, thereby improving thermal efficiency. The temperature field inside the furnace becomes more uniform, and the fuel burns more completely, thereby improving the efficiency of fuel utilization and achieving energy conservation and emission reduction. Common refractory bricks have an emissivity of only 0.4–0.7 under high-temperature conditions, resulting in a large amount of heat being lost to the surrounding environment through the furnace walls, which leads to energy waste. Insulation measures are usually employed to reduce the temperature of the kiln walls and minimize heat loss; this is a passive energy-saving remedy. High-emissivity coatings prepared from various high-temperature resistant materials such as cerium oxide, zirconium oxide, yttrium oxide, and silicon oxide maintain a very high emissivity over a wide temperature range, reaching above 0.9, thanks to the complementarity of their compositional properties and atomic doping techniques. If a high-emissivity coating is applied to the surface of the refractory bricks on the inner wall of the glass furnace, the emissivity of the furnace wall can be increased from 0.4–0.7 to over 0.9. A large amount of radiant heat is emitted back into the kiln, where it is absorbed by the materials at lower temperatures. This accelerates the heating of the materials, reduces their residence time, and improves production efficiency. Under high-temperature conditions, the reducing atmosphere and corrosive agents in the furnace also cause significant damage to the refractory materials, leading to phenomena such as pulverization and ablation of these materials. The high-emissivity coatings produced by Beijing Zhisheng Weihua utilize doping technology to form solid solutions at high temperatures, resulting in good adhesion to the substrate, a dense coating structure, and enhanced wear resistance and corrosion resistance. It is widely used in industrial equipment such as ceramic kilns, coal-fired furnaces, oil and gas furnaces, incinerators, regenerative balls, tunnel kilns, and mobile kilns.