Influence of the temperature of aluminum oxide micropowder modification with Al2O3 nanopowders on the optical properties and radiation resistance of coatings manufactured on their basis

Abstract

Influence of the temperature of aluminum oxide micropowder modification with Al 2 O 3 nanopowders in the interval 200-1000°С on the granulometric composition, diffusion reflection spectra in the wavelength range 360-2100 nm, and integral solar radiation absorption coefficient of coatings fabricated on the basis of these powders as well as on changes of these parameters upon exposure to electrons is investigated. It is demonstrated that with increase in the modification temperature, the average powder particle size decreases, the negative action is intensified, and the radiation resistance of coatings increases.

Investigation of Optical Properties and Radiation Stability of TiO2 Powders before and after Modification by Nanopowders of Various Oxides

“…The prepared samples were mounted in space environment simulator "Spektr" [15]. Since the sample interaction with atmospheric oxygen after irradiation can lead to "bleaching"-a decrease in concentration of formed absorption centers of oxide reflective powders, the diffuse reflection spectra (r λ ) were registered in vacuum (in situ) after irradiation with accelerated electrons (E = 30 keV, φ = 1Á10 12 cm À2 s À1 , F = (0.5, 1, and 2) Â 10 16 cm…”

“…Theoretical and experimental studies revealed [9][10][11][12][13][14] that the modification with nanopowders is sufficiently effective way to increase the radiation stability because they possess large specific surface and work as a "sink" for gathering electronic excitations formed during irradiation. However, the modification by nanopowders can lead to a deterioration of initial optical properties that can be induced by large absorption of native point defects in the UV and visible ranges and by absorption of chemosorbed gases in near-infrared (IR) range of spectrum.…”

“…An influence of the modification by nanopowders on photo-and radiation stability of reflective powders is discussed in [9][10][11][12][13][14]. There are no data about an effect of modification conditions (temperature and heating time, type, and concentration of nanopowders) on the optical properties of materials and their stability to an impact of ionizing radiations.…”