Effects of environmental factors on corrosion behavior of aluminum

Abstract

Aluminum, used as a material for heat exchangers in air conditioners, often has problems of leakage of refrigerant on the Al surface due to corrosion. The problems originate from pitting corrosion of the Al in an external environment. To understand corrosion problems, it is necessary to study the corrosion behavior of Al in various environments. In this study, the effects of environmental factors on the corrosion behavior of Al were studied by the surface analysis and electrochemical testing in 3.5 wt% NaCl solutions, with changes of dissolved oxygen, temperature, and concentration of Cl− and S ions. Among the external environmental factors, the presence of oxygen and the increase of Cl− ion concentration do not significantly affect the corrosion potential of Al, leading to an increase of only 1.1 and 6 times, respectively. There was a significant decrease in the corrosion resistance of Al, approximately 40 and 800 times, respectively, with the increase of concentration of S and temperature.

Evaluation of atmospheric galvanic aluminum corrosion in electrical transmission towers at different sites in the Valparaíso region, Chile. Wire‐on‐Bolt Test (CLIMAT)

“…The variation of the aluminum corrosion rate for the same zone is more noticeable in the Playa Ancha zone, as aluminum corrosion is more affected by environmental chloride and synergistically by the presence of environmental SO 2 . This results agrees with Jung et al, [ 31 ] who showed that, for aluminum in a 3.5% NaCl solution, the chloride ion does not significantly influence the corrosion potential of aluminum, but does influence the corrosion rate, which increases as a function of the increase in chloride concentration. Similar results were obtained by Peng et al [ 32 ] Furthermore, Wang et al [ 33 ] found that aluminum alloys, under coastal and industrial atmospheres, suffer greater atmospheric corrosion in the presence of environmental chloride than when compared with an industrial atmosphere.…”

“…However, environmental SO 2 content is higher in the Las Vegas and San Felipe sites as compared with environmental chloride content, which reflects the lower aluminum corrosion rates and previous investigations that reported coastal corrosion higher than in industrial areas. [31][32][33][34] In addition, the zones of Las Vegas and San Felipe have a lower TOW (τ 3 ) as compared with the other areas (τ 4 ), which leads to lower corrosion rate values.…”

Deterioration Mechanisms and Advanced Inspection Technologies of Aluminum Windows

“…Aluminum windows work in a complicated environment with multiple aggressive factors such as chloride ions, humidity, temperature, and mechanical loadings [ 23 ]. Different factors deteriorate aluminum windows and affect their working performance in different ways.…”

“…Since this unique solution functions as an electrolyte and there are potential chemical differences between aluminum and alloyed metal, electrochemical reactions are formed. A high chloride ion concentration leads to a low negative corrosion potential and low general corrosion resistance [ 23 ]. The type of cation combined with chloride ion also plays a vital role in facilitating the corrosivity of chloride ions, with an order of CaCl 2 > MgCl 2 > NaCl [ 30 ], as the hydrolysis of chloride salts leads to a decreased pH value in localized areas.…”