Investigation of structural and tribological characteristics of Ti6Al4V alloy applied micro arc oxidation process

In this study, the surface of the Ti6Al4V alloy was coated with ceramic oxide in two different solutions: phosphate-added (MAO-F) and aluminate-added (MAO-A), keeping all other parameters of the MAO process constant. The surface roughness and thickness of the coatings obtained after the MAO treatment were measured by 3D surface profilometer and Eddy-Current method, respectively, and phase compositions and surface morphologies were analyzed with XRD and SEM. For the determination of tribological properties, ball-on-disc etching technique with alumina (Al2O3) abrasive ball was used under three different loads of 1 N, 2,5 N and 5 N, under normal conditions and at room temperature. According to the results obtained, rough and porous coatings were formed on the Ti6Al4V alloy by the MAO process. The thickness and roughness values of the coatings varied depending on the electrolytic solution. The phase compositions of both coatings were found to consist of anatase, rutile and Ti metal from a small amount of backing material. The friction coefficients of the samples decreased with increasing load. The highest friction coefficient was obtained at 1 N load value in all samples. It was also found that the wear volume loss of the MAO-A sample under 1 N load was lower than the MAO-F sample. At 2,5 N and 5 N loads, the MAO-F sample exhibited a higher wear resistance than the MAOA sample.