Friction and Wear Properties of NiSi Alloy with Ti Addition at High Temperatures.

The tribological properties of NiSi alloy were studied at high temperatures. The effect of the addition of Ti was also analyzed. The surface composition was analyzed by Raman spectroscopy. The results showed that the friction coefficient decreased with the increasing temperature, and the wear rate changed slightly from 25 to 400 °C. However, the wear resistance of the alloys decreased sharply at 600 °C, and this was due to the decrease of the high-temperature strength and the severe oxidation of the alloys. Although the oxidation resistance of NiSi alloy decreased with Ti addition, the tribological property was improved by the addition of Ti. The NiSi alloy with 5% Ti addition had the best wear resistance at high temperatures as compared to pure NiSi alloy and with 10% Ti addition, and the wear rates of the alloys were in the order of magnitude of 10 mm/Nm. With the increase of temperature, the wear mechanism of pure NiSi alloy transformed from abrasive wear to oxidation wear. As the Ti content increased, the wear mechanisms of the alloys changed from abrasive wear to fatigue wear at low temperature, and oxidation wear and fatigue wear at high temperature.