In this study, suspension HVOF spraying is used to deposit TiO 2 nanoparticles on 304 stainless steel substrates. Spray parameters are varied, including spray distance and number of passes, to determine their effect on friction and wear properties as well as surface topography, microstructure, and phase composition. The spray parameters used, the microstructures observed, and the wear mechanisms of the nanostructured TiO 2 coatings are described in the paper.