Liquid Precursors Plasma Spraying of TiO₂ and Ce- Doped Ba(Zr_0.2Ti_0.8)O₃ Coatings

In this work was studied the suitability of Solution/Suspension Precursors Plasma Spray (SPPS) technique to produce titanium dioxide (TiO₂) and cerium doped barium zirconium titanate (Ce doped Ba(Zr_0.2Ti_0.8)O₃ or BZT) coatings. The precursors were sol-gel solutions typically employed to produce powders of those compositions. We report on the formation of porous TiO₂ coatings on stainless steel substrates. The microstructures found this coatings are characterized by features typically found in solution precursor plasma spray processes; a combination of melted and unmelted deposits and small hollow spheres. Transmission electron microscopy revealed submicron/nanocrystalline features forming those deposits. Anatase was the main crystalline phase present in the TiO₂ coatings. The rutile phase was also found in the coatings. The photocatalytic activity of the coatings was measured and compared with the results obtained for commercial anatase powders dispersed in liquid. Preliminary results obtained for Ce doped Ba(Zr_0.2Ti_0.8) O₃ coatings deposited on mild steel substrates showed microstructures and crystalline phases suitable for dielectric applications.