The tribological properties of nano-titanium obtained by hydrostatic extrusion

This paper reports the results of studies of wear resistance of nano-titanium Ti-Grade 2 obtained by hydrostatic extrusion. The tribological behavior was examined with the pin-on-disc tribometer under various lubricant conditions: in dry sliding contact, in normal saline solution (0.9% NaCl), and in paraffin oil. The changes of friction coefficient and linear wear of pins were measured during tests. The results confirmed the poor wear resistance of titanium, both nano-grained and initial Ti-Grade 2. Wear was dominated by material loss in the titanium pins. The observed distinction in tribological behavior of investigated materials is mainly due to differences in the tribochemical reactions occurring during friction under various lubricant conditions. The structure of wear debris appeared to also depend on the sliding conditions. Additional tests performed during dry sliding against UHWMPE indicated the favorable effect of HE process on titanium and proved excellent tribological properties of this frictional pair. (c) 2007 Elsevier B.V. All rights reserved.