Effect of Compaction Load and Sintering Temperature on Tribological and Mechanical Behavior of Ni/SiC/MoS2 Composites
In the present investigation, the effects of compaction load and sintering temperature on the tribological and mechanical behavior of Ni/20%SiC/7%MoS2 hybrid composites was studied. The density, compression strength, and hardness of the composites were evaluated and compared. The wear properties of the composites were evaluated for the test condition of 1 m/s speed and 10 N load using a pin on disk tribometer. The braking performance of the composites was evaluated in a subscale dynamometer for the 500 kJ energy condition. The microstructure and wear surface morphology of the composites were analyzed by stereo, optical, and scanning electron microscopes. From the results, the following important conclusions are drawn: (1) the compaction load of 1400 kN and sintering temperature of 900 degC are optimum to obtain the best combination of tribological and mechanical properties; (2) the properties such as density, compression strength, hardness, wear, and friction increase up to a critical sintering temperature, and then decrease later; (3) the composition and thickness of the interface reaction product phases (Ni2Si, Ni3Si, and graphite) play a key role in deciding the strength of Ni/SiC interface that consequently affects the mechanical and tribological properties of the composites; (4) the abrasive wear is found to be the main wear mechanism in the highly densified composites, whereas the delamination wear and the third body wear are major wear mechanisms in the poorly densified composites; and (5) the better braking performance of the highly densified composites is attributed to the absence of third body wear, controlled flow of solid lubricant, and lower porosity.
Journal of Materials Engineering and Performance