HiE-Coat 840-C is a high-temperature, high-emissivity blackbody coating used for installations of gas-fired, refractory-fiber-insulated furnaces to improve thermal efficiency for applications to 2500°F. It is applied easily to ceramic and refractory surfaces using a sponge brush, roller or conventional spray equipment. Curing is accomplished in operation or by heating for 1-2 hours at 200°F. The water-based, ceramic coating demonstrates an emissivity greater than 0.90 at temperatures up to 2500°F. High-temperature combustion chambers, ovens and furnaces constructed using high-emissivity coatings are more energy-efficient and distribute heat more uniformly.