Tribological properties, thermal conductivity and corrosion resistance of titanium/nanodiamond nanocomposites

Ti-based composites are finding ever-increasing applications as biomaterials because of their excellent performance. For this research, an attempt has been made to study the tribological, thermal and corrosion properties of Ti/nanodiamonds (NDs) nanocomposites. The powder mixtures were consolidated by spark plasma sintering process. Microstructure and composition of the samples were investigated by transmission electron microscopy and X-ray diffraction techniques. Based on the tribological results, wear rate decreased significantly with increasing NDs, especially at a load of 200 N. This was attributed to the strengthening of the nanocomposites by ND reinforcements. Wear mechanism is considered to be micro-ploughing and delamination for pure Ti as well as abrasive and adhesive wear for the Ti/NDs nanocomposites. In addition, thermal conductivity of the composites was evaluated as a function of ND amounts, showing reduction of the thermal properties with increasing the nano-reinforcements. According to the corrosion test results, corrosion resistance of the samples increases with increasing nano-reinforcement up to 0.25 wt% NDs and thereafter decreases. Therefore, there was an optimum for the amount of NDs in which the corrosion resistance of the Ti/NDs nanocomposite is at the highest level. Furthermore, it was deduced that micro-galvanic corrosion is the most predominant mechanism for this system.