Wear Properties of Electroless Ni-P Plated Al Alloy and Polyacetal

Abstract

Wear properties of an electroless Ni-P plated A2011 alloy and polyacetal have been examined. An electroless Ni-P plated layer is an amorphous material as plated and Vickers hardness of the layer was approximately 450HV. The microstructure of the electroless Ni-P plated layer changes into crystalline structure which disperses fine Ni₃P phases in a Ni matrix by heat treatment. Vickers hardness of the electroless Ni-P plated layer increases with increasing heat treatment temperature in the temperature range from 150°C to 350°C. Vickers hardness of the layer was approximately 1000HV after heat treatment at 350°C for 2h. In this study, a pin-on-disk type wear test was conducted using polyacetal and the electroless Ni-P plated A2011 alloy as pin and disk materials, respectively. From the results of wear tests, wear of polyacetal was only observed under the conditions investigated. Wear volume of polyacetal decreases with increasing Vickers hardness of the electroless Ni-P plated layer. Moreover, it was clarified that wear volume of polyacetal decreases to values lower than that using a conventional A2011 alloy with anodic oxide coating when Vickers hardness of the electroless Ni-P plated layer is over 600HV.