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.