Abstract
Corrosion of aluminum alloys in mortar containing sodium, calcium and chloride ions have been studied by weight loss and electrochemical measurements. The ions were added into mortar in the amount of 3%CaCl2 and 3%NaCl. The corrosion product of aluminum alloys in mortar containing 3%CaCl2 was identified as 3CaO·Al2O3·8H2O by X-ray diffraction. The corrosion was inhibited by precipitation of the corrosion product and the rate of corrosion was almost proportional to the passivation current. When both 3%CaCl2 and 3%NaCl were added in mortar, the corrosion product was found to be trihydrated aluminum oxide. The corrosion weight loss was approximately 3 times that in mortar containing 3%CaCl2 and one-fourth that in mortar containing no CaCl2 nor NaCl. It is concluded that calcium ions inhibit and sodium ions accelerate the corrosion of aluminum alloys in mortar.
