Preparation,mechanical property and wear resistance of Ni–W/Al 2 O 3 composite coatings

Ni–W/Al₂O₃ composite coatings were prepared by electrodeposition in Ni–W plating solution containing Al₂O₃ particulates. The content of codeposited Al₂O₃ particulates in the composite coatings was controlled by the addition of different Al₂O₃ concentrations in the solution. The mechanical property and wear resistance of Ni–W/Al₂O₃ composite coatings and Ni–W alloy coating were comparatively investigated. The results indicated that addition of Al₂O₃ particulates would lead to an increase in microhardness of the composite coatings. The present study shows that the codeposited Al₂O₃ particulates in deposit increase the wear resistance and reduce the wear weight loss. Moreover, the wear resistance of Ni–W/Al₂O₃ composite coatings is closely related with Al₂O₃ content in deposit. Namely, the composite coating with a lower Al₂O₃ content of 3·3 wt-% shows somewhat increased wear resistance compared with the Ni–W alloy coating, while the composite coating with a higher Al₂O₃ content has much better wear resistance than the Ni–W coating.