Titanium nitride induced wide temperature range self-lubricating silicon nitride ceramics with low wear and stable low friction coefficient

Abstract

Silicon nitride (Si3N4) with excellent mechanical properties and chemical stability, has been widely used in many fields. However, wear failure is often the cause of the short life of Si3N4 devices at high temperatures, thereby the wear resistance of Si3N4 ceramics still needs to be further improved. In this work, titanium nitride is used as a reinforcing phase to prepare wear-resistance Si3N4 ceramics in a wide temperature range by spark plasma sintering. The effect of TiN particles on densification process, phase transformation, mechanical properties, and tribological properties in wide temperature range from 25 to 800 °C were tested and analyzed. At room temperature, TiN particles hindered the propagation of microcracks, and the wear rate was reduced by an order of magnitude, reaching 3.69×10−6 mm3·N−1·m−1. At 800 °C, the completed TiO2 oxide film exhibited self-repairing and lubricating properties, which further reduced the wear rate to 9.35×10−7 mm3·N−1·m−1. Additionally, the friction coefficient of Si3N4 ceramics with 30 vol% TiN decreased considerably and remained stable in the wide temperature range of 25 ∼ 800 °C, with a range of 0.69 ∼ 0.85.