Phase transitions and diffuse reflectance spectra of barium titanate-zirconate solid solutions

The composition, structure, particle size distribution, diffuse reflectance spectra, integral absorption coefficients of solar radiation and dielectric properties of BaTi(1–x)Zr(x)O3 powders synthesized from micro powders BaCO3, ZrO2 and TiO2 at x = 0 – 0.3 have been studied. Changes in the integral absorption coefficient of the powders at different concentrations of zirconium cations were found to be within 34 %. Dielectric studies conducted over the wide ranges of temperature and frequency showed the presence of two phase transitions, one of them undergoing near the room temperatures. This fact makes it possible to consider these powders as pigments for thermal control coatings at operating temperatures of space crafts.