Fundamentals and analysis of high emissivity refractory coatings

The objective of the present paper is to analyze the patents produced by NASA and other related studies in the area of high emissivity refractory coatings, according to the fundamentals that rule the thermo-optical materials properties, which include: absorption, reflectivity, transmission and emission of electromagnetic radiation. Firstly, it aimed to understand these phenomena and their physical laws. Later, those concepts were applied to explain the trend observed in coatings of high emissivity used by NASA. Finally, it was understood that the material absorption index is determined by the way it interacts with the incident radiant energy. Furthermore, it was attested that the emissivity of the materials used are mainly associated to the balance between the absorption index and the reflectivity. This study and understanding of the technological evolution of refractory high emissivity coatings allow a deeper understanding of how they operate and their potential use in other systems, such as industrial furnaces lined with refractory material operating at high temperatures.

refractory coatings; emissivity