Near-isotropic air plasma sprayed titania Original Research Article

A titania feedstock was air plasma sprayed on low carbon steel substrates. In-flight particle temperature, velocity and diameter were monitored in order to find a parameter set that resulted in high particle temperature and velocity. Coatings were produced using the chosen parameter set, and certain mechanical properties (Vickers microhardness, Knoop microhardness and elastic modulus) of these deposits were measured on the cross-section and in-plane (top surface). The microstructure was evaluated using image analysis (porosity) and scanning electron microscopy. Thermal spray coatings are widely known for their anisotropic character, however, in this work, the mechanical properties of the titania coatings exhibited very similar values on the cross-section and in-plane regions. The reasons why this near-isotropic character is present are suggested and discussed.