Tribological behavior of Ni-Nb amorphous coating fabricated by mechanical alloying method

In this study, the microstructure, microhardness and tribological behavior of the Ni-Nb amorphous coating fabricated by mechanical alloying method were investigated at three annealing timepoints (30, 120, 240 min) at 650 °C. Annealing of amorphous coating for 30 min led to a reduction in microhardness. However, as annealing continued, the microhardness demonstrated significant growth. The changes were attributed to the formation of Ni3Nb and Ni6Nb7 nanocrystalline intermetallic compounds embedded in the amorphous matrix. The wear resistance of the coatings up to 120 min of annealing showed a similar trend with microhardness but no longer followed the microhardness trend after 240 min of annealing. The delamination and oxidative wear mechanisms were the dominant wear mechanisms for the as-prepared and annealed coatings. [Display omitted] •Crystallization of Ni-Nb amorphous coating was done at different annealing times.•The microhardness of the coatings decreased and then increased significantly by increasing the annealing time.•The wear resistance of the coatings indicated a similar trend with microhardness but with further increase of annealing time decreased.•The delamination wear and the oxidative wear mechanisms were the dominant wear mechanisms for the as-prepared amorphous and annealed coatings.