Effect of variations in Ni-W molar ratio on the microstructure, mechanical properties and tribology of electrodeposited Ni-W/diamond composite coatings

In this work, Ni-W/diamond composite alloy coatings were successfully fabricated on low carbon steel by using direct current (DC) electrodeposition. The Ni-W molar ratio was varied in the range of 0.22-2 in the plating bath. The effect of variation of Ni-W molar on the microstructure, mechanical properties and tribology of Ni-W/diamond composite coatings was analyzed. The obtained results show that the W content and deposition rate of the Ni-W alloy tends to decrease from 19.02 at. % to 2.1 at. % and 34.86 & mu;m/h to 11.98 & mu;m/h, respectively as the Ni-W molar ratio is increased from 0.22 to 2. The hardness results reveal that the highest microhardness of 1346 H-v was reported for the sample fabricated with 0.75 Ni-W molar ratio. Furthermore, the wear rate of the Ni-W/diamond coatings tends to show a significant reduction as the Ni-W molar ratio is increased from 0.22 to 0.75.