Effect of a Kind of Metal Cation on Corrosion Mechanism of A3003 Aluminum Alloy in Tap Water

Abstract

Effect of a kind of metal cation on corrosion mechanism of A3003 aluminum alloy in tap water was investigated by electrochemical techniques and immersion corrosion tests. Corrosion rate of the aluminum alloy decreased with increase in a hardness of cation, except for Mg 2+ . XPS analyses showed metal cations, classi ed as a hard acid in tap water were incorporated in hydroxides on the aluminum alloy. The results suggest that the incorporated cations have corrosion inhibitory effect (e.g., Ca 2+ and Zn 2+ ) or corrosion promotive effect (e.g., Mg 2+ ). These different effects can be explained by difference in molar volume between hard metal cation s hydroxide and aluminum hydroxide.

Auger electron spectroscopic analysis of corrosion products formed on A3003 aluminum alloy in model fresh water with different Zn2+ concentration

“…Commonly, Zn 2+ is categorized as a hard acid and OH − as a hard base; from this, it may be proposed that Zn 2+ easily bonds with the OH − on the Al 2 O 3 layer on aluminum alloys (Figure A). Our previous study established that a metal cation layer of Zn 2+ (10‐ to 15‐nm thickness) was formed on Al 2 O 3 in model fresh water containing Zn 2+ and that the metal cation layer had high corrosion protective properties (Figure B) . In the previous study, the polarization curve for A3003 aluminum alloy obtained in model fresh water containing Zn 2+ suggested that the metal cation layer of Zn 2+ on the aluminum alloy suppresses both the anodic (metal oxidation) and cathodic (oxygen reduction) reactions.…”

“…The formation and corrosion protection mechanism of the metal cation layer of Zn 2+ is detailed in Figure A and B. Several studies have reported that an Al 2 O 3 layer (5‐ to 10‐nm thickness) is formed on aluminum alloys and that the layer has OH − sites at the solution/Al 2 O 3 interface . Hard and soft acids and bases (HSAB) theory has reported that hard acids and hard bases form strong bonds .…”

“…This research has focused on the effects of metal cations and showed that the corrosion rate of A3003 aluminum alloy in fresh water is changed by the kinds of metal cations in the model fresh water where the concentration of Cl − , dissolved oxygen, and pH is similar. This research also established that Zn 2+ is superior to inhibit the fresh water corrosion of A3003 among the metal cations used in the studies . However, the minimum concentration of Zn 2+ to inhibit the corrosion of A3003 in model fresh water has not been determined.…”

“…The authors have been investigating the corrosion of aluminum alloys in fresh water focused on the effects of metal cations. [7][8][9][10] This research has focused on the effects of metal cations and showed that the corrosion rate of A3003 aluminum alloy in fresh water is changed by the kinds of metal cations in the model fresh water where the concentration of Cl − , dissolved oxygen, and pH is similar. This research also established that Zn 2+ is superior to inhibit the fresh water corrosion of A3003 among the metal cations used in the studies.…”

“…This research also established that Zn 2+ is superior to inhibit the fresh water corrosion of A3003 among the metal cations used in the studies. 9,10 However, the minimum concentration of Zn 2+ to inhibit the corrosion of A3003 in model fresh water has not been determined. Establishing the minimum concentration of metal cations is important to be able to use the metal cations in industrial environments as corrosion inhibitors.…”