Microstructures and functional properties of suspension-sprayed Al2O3 and TiO2 coatings: An overview

This paper presents an overview of current research activities regarding the properties and functionalities of finely structured alumina (Al2O3) and titania (TiO2) coatings prepared by suspension plasma spraying and suspension HVOF spraying. A selection of new experimental results obtained by the authors is also included. In the case of Al2O3, focus was on the retention of a higher content of the alpha-phase in the coatings without any post-treatment or alloying. For TiO2, the goal was to preserve the initial anatase phase in order to obtain photocatalytically active titania coatings. Coating microstructures, phase compositions, and functionalities resulting from the interactions between different working parameters are discussed.