Abstract
Nanostructured and conventional titania feedstocks were thermally sprayed using APS, VPS and HVOF techniques to study the effects of processing, microstructure and properties on the abrasion behavior. The in-flight characteristics (temperature and velocity) of the APS and HVOF-sprayed particles were also investigated. For the nanostructured coatings, a process map was developed relating the in-flight particle characteristics during coating deposition to the abrasion resistance. This map showed that the particle velocity and particle temperature had an important influence on the volume loss in abrasion tests. Coatings were characterized using SEM to investigate the microstructural features, image analysis to measure coating porosity and Vickers indentation to determine hardness. The abrasion behavior of the coatings was evaluated using the ASTM standard dry sand/rubber wheel test. The abrasion results indicated that the VPS and HVOF-sprayed nanostructured titania coatings exhibited the highest abrasion resistance among the 14 coatings studied.
