Investigation of the Surface Properties of TiN-Coated Ti6Al4V Alloy

Abstract

: Titanium alloys are widely used in the aerospace industry due to their good mechanical properties. Especially Ti6Al4V alloy is preferred in machine parts that require specific strength in aerospace. However, the tribological properties of the Ti6Al4V alloy are poor and need improvement. It is possible to increase the life of Ti6Al4V alloys and improve their surface properties with various heat treatment and surface coating techniques. For this purpose, in this study, plasma nitriding heat treatment was first applied to the samples prepared from Ti6Al4V alloy. Then, TiN coating was carried out by the magnetron sputtering method. Surface roughness and surface hardness were measured before and after coating. Wear tests were performed with dry friction and room temperature conditions on Ti6Al4V alloys using the sliding velocity and normal load as variable parameters. The wear track widths, the weight loss of the samples, and the abrasive disc were measured. The steady‐state sliding regime average friction coefficients were determined from the recorded friction forces depending on the sliding distance. Normal load ‐ wear track widths, normal load ‐ friction coefficient graphics were created. Load wear track width plots showed that the wear track widths on the TiN coated and uncoated samples increased with the load. The fact that the track width values of the uncoated samples with the same load and velocity values were higher than the TiN‐coated samples showed that the TiN‐coated samples had higher wear resistance. In addition, it was observed that the friction coefficient values in the uncoated samples under constant sliding speed were relatively higher than the TiN‐ coated samples