Electrical and Optical Properties of Plasma-Sprayed Yttria

The aim of this study is to investigate electrical properties of Yttria which is known for its outstanding thermal and chemical stabilities. Y2O3 coatings deposited on carbon steel substrates were prepared using an atmospheric plasma-spray system. Three sets of samples were sprayed and characterized in order to determine their microstructural, electrical, and optical aspects of sensitivity to spray distance. All coatings contained only cubic Y2O3 phase and exhibited weak influence of spray distance variations on electrical properties. Relative permittivity values varied between 9.3 and 11.2 in the whole frequency range (50 Hz to 1 MHz) for all samples. Temperature dependence of electrical properties in the range of 20 °C to 120 °C showed good stability of measured values. Electrical resistivity was in the order of magnitude up to 10 × 1012 Ω m for all the samples. SEM observations, porosity, and reflectivity measurements brought an expanded view of microstructural changes at different spray distances.