Evaluation of hydrogen permeation in fretting corrosion interfaces with Ti-6Al-4V alloy and varying lubricants using a modified Devanathan-Stachurski cell

Titanium alloys are commonly used in biomedical applications for structural components such as hip femoral stems and acetabular cup shells. Whilst the fretting-corrosion degradation of titanium (Ti)-alloys has been well documented, the role of hydrogen permeation within these contacts has not received much attention despite evidence in clinical retrieval studies. This is likely due to the complexity of measurement and simulation. The aim of this study was to better understand the effect of tribological and electrochemical mechanisms on hydrogen permeation. A novel detection cell based on the Devanathan-Stachurski (DS) cell was designed to investigate hydrogen permeation in fretting corrosion contacts found in titanium-aluminum-vanadium (Ti-6Al-4V) alloy. Hydrogen permeation was found to be dependent on the amplitude of fretting displacement. Hydrogen permeation was not detected at lower amplitudes (10 and 50 μm); whereas, a significant increase in hydrogen permeation was found at 150 μm displacements. Furthermore, hydrogen permeation was found to be affected by the components of the tested physiological saline solution. Presence of hydrogen permeation was noticed in 0.9% sodium chloride (NaCl) and physiological saline combined with albumin protein. However, the amount of permeated hydrogen was reduced (38%) when hydrogen peroxide (H2O2) was added. While corrosion rate and hydrogen permeation increased (6%) significantly when both albumin and H2O2 were added to the solution. These results show that fretting induced hydrogen ingress can be simulated and detected in situ within simulated aqueous environments. Furthermore, a framework to assess the interactions between fretting and hydrogen ingress, which can be translated to other industrial challenges, has been developed.