Tribological evaluations of spark plasma sintered Mg–Ni composite

Elemental nickel particle was incorporated into magnesium matrix using blend-spark plasma sintering powder metallurgy technique without the use of ball milling and its effect on the hardness and tribological behaviour of magnesium was evaluated. Ball-on-disc wear tests were carried out using a 440C hardened stainless steel ball as a counter-face with a constant linear speed of 0.1 m/s under varying normal loads of 2.5, 5 and 10 N, respectively. The wear track on the disk samples was characterised using a FESEM equipped with energy dispersive spectrometer to investigate the wear mechanisms and features. Results showed that the reinforced magnesium composite showed excellent tribological properties as compared to the monolithic samples in terms of a reduction of up to 27.5% in the coefficient of friction and a reduction of up to 53.7% in weight loss. Microstructural analysis of the wear track established different wear mechanisms of abrasion, adhesive, delamination and oxidative wear.