Tribological performance of spark plasma-sintered niobium carbide (NbC) under optimized sliding conditions: Wear mechanisms and debris characterization

This experimental study used Niobium Carbide (NbC) as the base material to evaluate the wear characteristics of Spark Plasma Sintered (SPS) NbC pellets against a silicon carbide (SiC) abrasive sheet as the counter surface, using a rotary pin-on-disc wear analyser in accordance with ASTM G99. Initially, NbC samples were sintered at four different sinter temperatures of 1550°C (NbC-0.63T m ), 1640°C (NbC-0.66T m ), 1700°C (NbC-0.69T m ), and 1780°C (NbC-0.72T m ), respectively, below the melting point of niobium (2477°C). The Box-Behnken Design (BBD) method was employed to study the wear behavior by varying the sliding distance (150, 300, & 450 m), applied load (1.0, 1.5, & 2.0 kg), and speed (0.5, 1.0, & 1.5 m/s). Subsequently, the input parameters were optimized using the BBD approach to a sliding distance of 350 m, an applied load of 1.5 kg, and a speed of 1.0 m/s to attain the minimum wear rate. The findings reveal that sintering temperature significantly influences the wear rate of NbC. The NbC-0.72T m sample sintered at the highest temperature exhibited the lowest wear rate of 0.43 × 10 −5 mm 3 /m.