Effect of pH and Concentration on Electrochemical Corrosion Behavior of Aluminum Al-7075 T6 Alloy in NaCl Aqueous Environment

In the present study, corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical in 1.75% 3.5% NaCl environment at acidic, neutral basic pH. The data obtained both tests (potentiodynamic polarization impedance spectroscopy tests) that rate specimens is minimum for pH=7 condition solution due to formation dense well adherent thin protective oxide layer. Whereas solutions with acidic alkaline pH cause shift more active domains aggravated constant flux ions (Cl− OH−) media which anodically dissolve Al matrix comparison precipitated intermetallic phases (cathodic nature) formed T6 treatment. Consequently, pitting alloy, as observed cyclic tests, shifts regions when changes from localized dissolution ingress diffusion through pores film. Microscopic analysis also strengthens results study examines this under a systematic evaluation marine environment.