Indirect monitoring of the dynamics at the contact interfaces of a pair of abrading titanium specimens

The novel method of using continuous tribo-electrification variations to monitor the dynamic tribological properties between metal films has been applied successfully [Y.P. Chang, A novel method of using continuous tribo-electrification variations for monitoring the tribological properties between the pure metal films, Wear, 262 (2007) 411-423]. The method was shown to produce clear and strong signals, superior to monitoring continuous friction coefficient variations. However, the above method was only shown to be suitable for the tested material pairs that were studied. In this paper, the method was improved and applied to monitoring the dynamic tribological properties between titanium oxide (TiO2) films in the friction process. The experiment was conducted on a purposed-designed friction tester with a suitable measuring system. In order to investigate the tribological property of titanium (Ti) sliding against Ti with TiO2 films in detail, the continuous variations of electrical contact resistance and friction coefficient were measured for monitoring the onset of film rupture between the TiO2 films and the chemical reactions between the interfaces. Wear loss was measured by an accuracy balance and scan electron microscopy was used to observe the microstructures and material transfer. The experiments demonstrated that the novel method of using electrical contact resistance variations has great potential for monitoring the dynamic tribological properties and the chemical reactions of titanium specimens.