Emissivity of “Grey” Bodies, Surface Roughness and other Measures

The Stefan-Boltzmann law quantifies the radiating energy of a body, but this requires knowledge on emissivity. The surface emissivity values more often are determined using instruments in a test or experiments. This procedure may not be practical for large objects that are difficult to mount in a laboratory. This paper reviews the different concepts and dimensions that affect emissivity. This explores the relationship of emissivity with the selected thermodynamic properties, dimensions including the surface microstructure of the material. Thermodynamic properties and surface microstructure images from online sources were utilized as data for the selected materials. Field Emission Scanning Electron Microscope (FESEM) provides the rest of the unavailable images. Fractal image analysis characterized and gave dimension to the roughness of the surface microstructure of the material. Different regression models of the relevant dimensions were tested to determine the statistical relation and the optimum correlation to emissivity. Overall, the calculated values of the emissivity model of the study yields strong correlation with the published emissivity values.