Tribological behaviour of Fe-C-Ni self-lubricating composites with WS2 solid lubricant

This paper reports an investigation on the friction and wear behaviour of novel Fe-C-Ni based self-lubricating composites. The effect of tungsten disulfide (WS2) as a solid lubricant and its content on the tribological behavior of the sintered Fe-C-Ni material was studied. Fe-0.3C-2Ni based composites were developed by powder metallurgy technique. WS2 with varying weight fractions (3, 5, 7 and 9 wt%) was incorporated in the Fe-C-Ni matrix. The hardness and compression strength properties of the composites increased with the increase in the weight fraction of WS2. Friction and wear behaviour of the fabricated composites were evaluated under dry sliding conditions. It was observed that the coefficient of friction and wear of the test samples decreased with the increase in the wt% of WS2. The composite with the highest amount of WS2 (i.e. with 9 wt% WS2) showed the lowest value of coefficient of friction (0.47) and the lowest value of wear (1.05 × 10−3 g). Scanning electron microscopy of the worn surfaces of the test materials revealed: (i) adhesion as the wear mechanism in the Fe-C-Ni material and (ii) abrasion and delamination as the wear mechanisms in the composites. It is evident from the results of the present investigation that the developed Fe-C-Ni-WS2 composites have effective self-lubricating capability, and that by increasing the WS2 content, both their mechanical and tribological properties can be enhanced.