Pin-on-Disk Wear Investigation on Bronze Coating – Part 1: Definition of the Test Methodology

Some tests have been performed with a pin-on-disk experimental apparatus to define the methodology to be used in a successive experimental campaign for investigating friction and wear performances of new materials, coatings, and surface textures. The pin-on-disk drive of a multi-function tribometer is used with a bearing steel ball pressed against the bronze coating of a disk. The test conditions have been selected based on a preliminary analysis of the most used standard for pin-on-disk tests. A velocity of 0.1 m/s, a normal load of 10 N and a sliding distance of 1 km has been chosen. Wear depth and friction coefficient are continuously monitored and recorded during tests. After tests wear volume estimation is performed with two different approaches: the gravimetric and the volumetric ones. Further information on wear evolution is provided by the 3D reconstruction of the worn track obtained in additional tests involving interruptions and restarts by using the optical interferometry system of the multi-function tribometer. The preliminary results evidence the influence of the initial surface condition and of the radius of the track. The presence of an oxide layer on the coating produces a delay in the start of significant wear and some friction fluctuations. As expected, reduced wear depth and a marginally grater wear volume is obtained with the larger track radius.