Effective corrosion protection of aluminum alloy AA2024-T3 with novel thin nanostructured oxide coating
Maido Merisalu, Lauri Aarik, Jekaterina Kozlova, Hugo Mändar, Aivar Tarre, Väino Sammelselg
Abstract
Effective corrosion protection via a thin ceramic coating on an Al-alloy AA2024-T3 is demonstrated. The preparation of the coating consists of two steps. First, with a special anodizing process, a chemically homogeneous thin base layer is formed on the substrate. Then, the nanoscale pores in the base layer are sealed, and the entire surface is covered with a chemically resistant Al2O3/TiO2 nanolaminate using atomic layer deposition. The sample surface is thoroughly characterized, including linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) and testing by long-term immersion in a salt solution. The coating withstands LSV up to 10 V versus saturated calomel electrode (SCE) and salt solution immersion of 7152 h (298 days).