The present investigation studies the effects of heat treatment temperature on the corrosion behavior of cold worked 6111 aluminum alloy. The specimens were cold worked at different cold working ratios, namely, 10, 20, and 40%. They were then heat treated at 100, 200, and 400°C. Corrosion tests were performed using tap water with 0.01 M sodium hydroxide, as a corrosive medium, and the weight loss of the corroded specimens plus the corrosion rates were then calculated. Experimental results showed that corrosion rates depended on the amount of cold working percentage and the heat treatment temperature. Corroded surfaces were also photographed and analyzed. The graphs revealed large numbers of corrosion pits, in addition to crevice corrosion and fine grains of rust, and these rusts were cultivated to scales that were detached from the surfaces and were subjected to corrosive medium.

A simple and rapid method of fabricating Mg(OH)2 layer by chemical immersion was developed to improve the corrosion resistance of the magnesium alloy AZ31. The fabricated surface was superhydrophobic with a self-assembled monolayer coating of silane. The surface characteristics were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). The average water contact angle and sliding angle were determined to be 160° and 7° respectively as a result of wettability test. Potentiodynamic polarization indicated that both Mg(OH)2 layer and the thin layer of air were effective in improving anti-corrosion. This method which is efficient with regard to time and cost would be useful for magnesium industries and its application

A method for evaluating the safety of the corrosion fatigue of a high-pressure (HP) drum for the heat recovery steam generator (HRSG) is presented through a transient thermal stress analysis. To evaluate the corrosion fatigue, European Standard EN 13445-3 is applied to check whether the magnetite protective layer on the water-contacting surface can be preserved during the transient operating conditions: cold start, hot start, warm start, and load change. Static analysis is performed to analyze the stress due to the operating pressure, and transient thermal and structural analyses are performed for the transient operating conditions. As per EN 13445-3, the analyzed maximum and minimum stresses of the transient operating conditions at representative locations are compared with the allowable limits derived from the stress due to the operating pressure. In conclusion, the magnetite protective layer was preserved under the transient operating conditions and the HP drum was found to be safe for the corrosion fatigue. The method of analyzing the thermal stress and evaluating the safety of the corrosion fatigue presented in this research can be applied effectively in the design stage of various unfired pressure vessels exposed to high temperature and high pressure loading.