Microstructure characterization and tribological behavior of anodized ti6al4v alloy.

Abstract

Thin  oxide  layers  were  obtained  in  Ti6Al4V  alloy  by  anodizing  process  in  phosphoric  acid  with  different  currents and anodizing times. The oxide layers were characterised by X-Ray Diffraction, Optical Microscopy and Scanning Electron Microscopy, as well as by surface roughness and porosity measurements. The tribological response of anodized samples under lubricated sliding contact was studied in a pin-on-disc tribometer, in which UHMWPE discs were the counter bodies and Ringer ́s solution was the lubricant.The results showed that the oxide layers obtained were amorphous with average pore size smaller than 1μm and the pore morphology was affected by the anodizing current. The average surface roughness (Ra) varied between 0.02 and 0.10μm, and the oxide thickness varied between 0.5 and 0.88μm. The treated Ti6Al4V – UHMWPE pair showed friction coefficients in the range between 0.03 and 0.07, while a maximum coefficient of 0.02 was measured in the experiments carried out with untreated samples.