Effect of calcium carbonate modification on its reflectivity and radiation resistance

Calcium carbonate has high reflectivity and radiation resistance and is of great interest as a pigment filler for thermal control coatings of spacecraft. This work presents a comparative analysis of two different modifications of CaCO 3 : synthetic calcite and natural aragonite. The phase, elemental, and granulometric composition of the initial powders were investigated; diffuse reflectance spectra, as well as difference spectra, were obtained before and after irradiation of CaCO 3 samples with accelerated electrons at an energy of 30 keV and a fluence of 1·10 16 , 2·10 16 , and 3·10 16 cm −2 . The values of the integral absorption coefficient of solar radiation а s and its change Δа s , of calcite and aragonite powders after irradiation were determined. The structure of the CaCO 3 samples before and after irradiation was studied using infrared spectroscopy.