Microstructure and Properties of Plasma-Sprayed Mixture of Cr2O3 and TiO2

Abstract

Rutile TiO2 and Eskolaite Cr2O3 powders were mechanically mixed and fed into the plasma jet simultaneously. The influence of the ratio of components on behavior of the plasma-sprayed coatings was observed using two different compositions, both at two different feeding distances. The produced coatings were analyzed by XRD, SEM, XPS, and light microscopy. Electrical resistivity was measured at voltages from 1 to 100 V. Photocatalytic decomposition of butane on the coatings was studied using visible light together with a setup typically used for UV-light tests. For the coatings with high TiO2 content, besides rutile, low anatase content was identified. The coatings with predominant Cr2O3 exhibited lower porosity and higher hardness. All coatings are relatively efficient photocatalysts for butane decomposition. Moreover, they have good mechanical properties governed predominantly by Cr2O3 content as the harder component. It was proven that the spray process led to obtaining of robust photocatalytically active coatings.