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The radiation resistance and optical properties of micron-sized mCaSiO3 wollastonite powders (initial and modified by gadolinium oxide nGd2O3 nanoparticles) were studied. For this purpose, the powders were irradiated with accelerated electrons, and diffuse reflection spectra (ρλ) were recorded in high vacuum (in situ). The mCaSiO3 powder features a high reflectance throughout the measured spectrum range from 200 to 2,500 nm. The obtained value of the solar absorptance (αs = 0.117) is less compared to known powders used as pigments for reflective coatings, such as ZnO and TiO2. Depending on the concentration of nanoparticles in the range of 1–10 wt%, the radiation resistance of the modified mCaSiO3/nGd2O3 powder increases up to 1.7 times compared to the unmodified powder. The achieved increase is of great practical importance for various applications, which require high radiation resistance, such as nuclear industry (cement and ceramics fillers, dosimetry materials) and aerospace industry (pigment for thermal control coatings). [ABSTRACT FROM AUTHOR]

The purpose of the paper is to study the efficiency of modification with CeO2 nanoparticles (average particle size — 20–30 nm) in a concentration range from 0.1 to 10 wt.% aimed at improving the optical features and radiation stability of micron-sized ZnO powders. The optimal concentration of CeO2 nanoparticles, 3 wt.%, was determined. The change of the solar absorptance in a range of 0.2 to 2.2 µm after electron irradiation of the modified powder (E = 30 keV, F = 2·1016 cm−2) is 1.41 less compared to the unmodified powder. The paper demonstrates that the increase in radiation stability of zinc oxide powders modified with cerium dioxide nanoparticles is provided by two mechanisms: relaxation of primary defects on nanoparticles and capture of formed free electrons by cations of a rare-earth element. [ABSTRACT FROM AUTHOR]