Corrosion and Tribocorrosion Performance of Pack-Carburized Commercially Pure Titanium with Limited Oxygen Diffusion in a 0.9% NaCl Solution

Abstract

In the research presented, the corrosion and tribocorrosion characteristics of pack carburized titanium with limited oxygen diffusion (PCOD-Ti) has been investigated using a 0.9 % NaCl solution. The carburization treatment was undertaken using a service temperature of 925 ℃ for duration of 20 h. The treatment resulted in the creation of a titanium carbide (TiC) network layer atop an extended oxygen diffusion zone (ODZ) (α-Ti(O)). Electrochemical testing indicated the treated titanium surface offered slightly enhanced corrosion resistance over that of untreated titanium. Tribocorrosion testing of the PCOD-Ti was conducted by sliding the titanium against an alumina counter-face under a contact load of 20 N, with various anodic and cathodic potentials applied. The testing showed a dramatic reduction in the wear rate for the treated titanium. Wear rates were reduced by an order of magnitude when compared with the untreated samples. During testing an interesting cathodic protection was encountered. When subjected to high negative charge the wear rates of the treated titanium were reduced further. This reduced wear was attributed to the formation of titanium hydride within the wear track.