Effect of Potential on Corrosion Behavior of Tartaricsulphuric Acid Anodized 7075 T6 Aluminum Alloys

Anodizing of aluminum alloy in tartaric-sulphuric acid (TSA) is studied as an alternative to replace chromic acid anodization (CAA) to obtain more environmentally-friendly process. Bare 7075 T6 aluminum alloy specimens were anodized in TSA and subsequently protected by boiled water sealing treatment. The TSA solution used contains 86,76 gpl tartaric acid and 44 gpl sulphuric acid at 37°C. Some specimens are anodized in CAA as comparison. In this research, the effect of anodization potential of 7075 T6 aluminum alloy in TSA on the thickness, weight, and corrosion resistance of anodize layer are studied. Corrosion resistance test was carried out by conducting salt spray test for 96 hours and corrosion potential and current density measurement using potentiostat. The morphology and chemical composition of the sealed anodize layer were evaluated by scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The results showed that the thickness and weight of the anodize layer increases as the anodization potential increases. The best corrosion resistance is achieved by 7075 T6 aluminum alloy specimen with potential anodization of 15 V.