Tribo-corrosion behaviors of Ti3SiC2/Si3N4 tribo-pair in hydrochloric acid and sodium hydroxide solutions

This paper is a continuation of our work to characterize the tribo-corrosion behaviors of Ti3SiC2 in common acids and alkalis [Ren et al. (2010) [1]]. Tribo-corrosion behaviors of Ti3SiC2/Si3N4 in hydrochloric acid (HCl) and sodium hydroxide (NaOH) with different concentrations were investigated in the present paper. The worn surfaces of Ti3SiC2 and Si3N4 were examined using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that oxide films form on the worn surfaces of both Ti3SiC2 and Si3N4 by corrosive oxidation and/or tribo-oxidation. The SiO2 film, however, does not effectively prevent grains from detaching. Mechanical wear dominates the friction process rather than chemically corrosive wear for Ti3SiC2. Chemically corrosive reactions, in turn, decelerate mechanical wear to a certain extent. Corrosive wear resulting from oxidation and dissolution of material by corrosive solutions and mechanical wear from abrasion contribute to material loss for Si3N4. The high viscosity of NaOH solutions decreases friction and wear. (C) 2011 Elsevier B.V. All rights reserved.