Abstract
It is generally known, that aluminum and aluminum alloys do not corrode easily in a normal environment.
However under certain circumstances where either the humidity or industrial pollution is high, corrosion will occur on the surface of aluminum. Thus, this study examines the corrosive effect on aluminum contacted with natural water (drinking water, spa water, sea water, sweat and water passing through a concrete slab). The characteristics of aluminum corrosion products by contact with natural water were examined by X-ray diffraction and scanning electron micrograph methods and electrochemical polarization curves were obtained by using on electrochemical polarization apparatus. The following facts have been found through this experimental study: (1) The Al corrosion product in drinking water is amorphous: (2) The Al corrosion product by sulfrated spa water is crystalline and is a compound of KAl(SO4)2·2H2O, while that in chlorided spa water is amorphous: (3) The Al corrosion product in sea water is crystalline of Al(OH)3 and that in sweat is amorphous: (4) The Al corrosion products in water passing through a concrete slab are Al(OH)3 (Bayerite) and others. Anodic polarization curves have been obtained to examine the influence of Cl- and SO42- on initial corrosions of Al alloys 1050 and 6063 in spa water and sea water, and on corrosion of alloy 6063 of three different concentrations of water passing through a concrete slab.
