Corrosion and wear interplay: Tribo-electrochemical evaluation of NiTiNOL60 alloy in sulfuric acid

The combined corrosion and wear behaviour of NiTiNOL60 alloy is important in various engineering applications. While previous studies have explored its performance in artificial seawater environments, limited information exists regarding its tribocorrosion characteristics in acidic conditions. This paper investigates the synergistic interaction between sliding wear and electrochemical processes for NiTiNOL60 alloy in a sulfuric acid environment, employing experimental procedures compliant with ASTM standards. Microscopic analysis confirms the alloy's Ni-rich composition, featuring a dense network of B2 NiTi + Ni₄Ti₃ cubic and rhombohedral crystal matrix structures. Our research and results reveal that material degradation during tribocorrosion arises from the combined effects of sliding wear and electrochemical reactions. Consequently, multiple wear mechanisms influenced by tribochemical wear are observed, with delamination and micro-cracks being notably prominent under higher applied loads due to surface tensile stress and contact pressure, leading to crack propagation perpendicular to the sliding direction. These findings have practical implications for optimising the performance and durability of NiTiNOL60 alloy in acidic environments, offering valuable insights for load-bearing engineering applications.