Co-deposition of Wand Mo in electroless Ni-B coating and its effect on the surface morphology, structure, and tribological behavior

摘要

The Ni–B binary alloy deposited by autocatalytic chemical deposition technique has tremendous potential of wear/friction reduction and wide industrial usage. A significant improvement in mechanical properties, higher hardness, and wear resistance can be achieved in electroless nickel coatings by deposition of poly-alloy coatings rather than the binary variant. The present work therefore investigates the outcome of co-deposition of both tungsten and molybdenum in binary Ni–B coatings on the morphology, structure, and tribological behavior. Ni–B–W–Mo poly-alloy coatings were deposited by chemical reduction on AISI 1040 steel. Ni–B–W and Ni–B–Mo ternary coatings were also deposited along with Ni–B for effective comparison. Tribo-tests in the as-deposited and heat-treated condition (400°C for 1 h) revealed that the anti-wear properties of Ni–B–W and anti-friction properties of Ni–B–Mo could be realized in Ni–B–W–Mo coatings. Also, Ni–B–W–Mo coatings were observed to have high W content and a compact defect-free surface morphology with dense nodules. Backscattered electron images of the worn surface of the Ni–B–W–Mo coating in the as-deposited and heat-treated condition revealed low deformation of the coating with mild abrasion and an excellent overall tribo-performance.