Investigation of tribological properties of composite coatings produced by plasma transferred arc (PTA) method on the surface of Ti6Al4V alloy

In this study, the Ti6Al4V alloy surface was alloyed with TiC and C powders mixed in different volume proportions by plasma transfer arc (PTA) welding method. The microstructures of coated and untreated samples were examined by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and Xray diffraction (XRD) analyses. Microhardness values were measured from the coating area to the substrate material in the surface alloyed samples and a microhardness-distance graph was created with these data. Wear and friction surface properties were determined using the pin-disk wear test method according to ASTM-G99 standards. The surfaces of the wear tested samples were examined with SEM and EDS and the wear mechanisms were determined. As a result of this study, it was found that a good metallurgical bond was formed between the coating area and the substrate material in the samples whose surface properties were changed by the plasma transfer arc (PTA) welding method and the surface microstructure was changed. Among the samples, the hardness value was measured the highest in the sample coated with TiC powder, and the microhardness value was increased by an average of 2 times compared to the main material. It was determined that the sample with the lowest friction coefficient was the sample coated with graphite powder, while the sample with the highest wear resistance was the sample coated with titanium carbide powder. The wear resistance of the sample coated with titanium carbide increased approximately 11.5 times compared to the main material