Nanostructured and Conventional Cr₂O₃, TiO₂, and TiO₂-Cr₂O₃ Thermal Sprayed Coatings for Metal Seated Ball Valve Applications in Hydrometallurgy

This study evaluates candidate coatings for potential use in the manufacture of metal-seated ball valves for hydrometallurgy service. All coatings were deposited on grit-blasted titanium coupons by air plasma spraying to a nominal layer thickness of 500 µm. The feedstock powders used were selected based on literature review and field experience and include Cr₂O₃, TiO₂-Cr₂O₃, nano TiO₂, and a novel mixture of nano TiO₂ and conventional Cr₂O₃. The resulting coatings are compared based on microhardness, shear strength, friction properties, and wear resistance. Specimen preparation procedures and test methods are described in the paper along with the findings and potential implications of the study.