Study on characteristics of Ni-W-B composites containing CeO2 nano-particles prepared by pulse electrodeposition

Ni-W-B composites containing CeO2 nano-particles on the surface of 45 steel were prepared by pulse electrodeposition, and the influence of pulse frequency, pulse duty circle and heat treatment temperature on the structures and properties were investigated. The results indicated that the pulse co-deposition of Ni, W, B and CeO2 nano-particles led to Ni-W-B/CeO2 composites possessing higher microhardness and better wear resistance when heat-treated at 400 degrees C for 1 h. The microhardness of 636 HV and the deposition rate of 0.0281 mm/h of the as-deposited alloy were the highest at pulse frequency of 1000 Hz, pulse duty circle of 10% and pulse average current density of 10 A/dm(2). The composites were mainly in the amorphous state and were partially crystallized as-deposited, and the crystallization trend was strengthened when heat-treated at 400 degrees C. Decreasing pulse duty cycle from 75% to 10% was favorable to the refinement in grain structures and improvement of microstructures. The crystal sizes of the composites were smaller by means of pulse electrodeposition.