Effect of Pretreatment on Aluminum Etch Tunnel Structure

초록

Pitting is a common observation in aluminum corrosion. Aluminum pits show a unique geometry as a result of anodic etching in hot HCl solution. Cubic dth pits are initially formed in the early stage of etching and become tunnel-like structure afer etch times of several seconds. Electrochemical tunnel etching of aluminum has been used for manufacturing an aluminum electrolytic capacitor to creat a high surface area. Surface area of aluminum is closely related with tunnel morphology, which depends on microstructure of the aluminum and etching conditions. Prior to electrochemical etching of aluminum, Al has been treated in either passivating solutions or aggressive environments to increase the tunnel density. In this work, the effect of chemical and electrochemical pretreatment on pit formation was investigated.