Effect of orthophosphate addition on the tribocorrosion of copper in synthetic tap water solution

• Tribobocorrosion of copper is affected by inhibitor in solution.
• The tenorite phase leads to a less wear material loss than cuprite oxide.
• Tenorite limits the corrosion contribution in the tribocorrosion system.

This work investigates the role of orthophosphate as an inhibitor in the tribocorrosion of a copper alloy. Experiments were performed on reciprocating sliding test with a mechanical and chemical inert counter body. The electrolyte simulates the anionic species found in the local city drinking water. The influence of the orthophosphate on the oxide film formation is firstly described by a classic electrochemical approach. The results indicate that oxide morphologies and corrosion resistance depends on the insertion of orthophosphate in the solution. The sliding tests done at cathodic potential lead to a mechanical wear which is independent of the electrolyte. However, a change of the coefficient of friction appears with the orthophosphate. The benefit of the inhibitor is then studied under anodic potential. A minimum of wear is reached with it. Even if the part of the corrosion-accelerated wear is prevailing in the tribosystem, orthophosphate limits the corrosion phenomenon.