A comparative study on wear behavior of TiN and diamond coated WC-Co substrates against hypereutectic Al-Si alloys

The demand for better tools for machining hypereutectic aluminum-silicon (Al-Si) alloys are increasing day by day since the extensive use of these alloys in internal combustion engines. In addition to the lifetime of the machining tool, surface finish of the machined piece is also equally important, as it directly affects the performance of the engine. In this paper, we compared the wear behavior of bare tungsten carbide (WC-Co), titanium nitride (TiN) coated WC-Co and diamond coated WC-Co substrates against Al-Si alloys using pin-on-disc method. Both TiN and diamond coatings were done using chemical vapor deposition technique. Diamond coated WC-Co substrates show one order less wear loss compared to the bare WC-Co substrates. Instead of weight loss, a weight gain was observed for the TiN coated WC-Co substrates. Average coefficient of friction was lowest for the diamond coated WC-Co substrates due to the different wear behavior of diamond coated tribological system, which is explained in detail.

► Wear behaviors of diamond/WC-Co, TiN/WC-Co and WC-Co against Al-Si were studied. ► Both TiN and diamond coatings were done using chemical vapor deposition technique. ► Friction and sliding wear properties were characterized using a pin-on-disc method. ► Diamond coated WC-Co pins showed one order less wear loss than bare WC-Co pins. ► A weight gain was observed for the TiN coated WC-Co pins. ► Average coefficient of friction was lowest for the diamond coated WC-Co pins.