Effect of hardness and abrasive properties of TiO2 anodized with HCl and heat treated

Abstract

Grade 2 titanium was anodized with HCl, producing a TiO2 layer containing nanotubes. After annealing at various temperatures between 400 and 800 °C, the nanotubes in the layer were transformed into oxide grains due to a sintering process. It was determined that the anatase phase is present in the layers with formation of nanotubes and/or nanoparticles, while the rutile phase is present especially in the oxide layer and grains. After annealing at 800 °C, the anodized layer improved the hardness of titanium by almost 4 times, however, for the layer annealed at 700 °C the wear rate was found to be 2 orders of magnitude lower than for titanium, and therefore it was considered to have the best performance.