The Chemical Nature of Aluminum Corrosion. I. Activation of Aluminum Surfaces by Aluminum Salts

摘要

The activation of aluminum surfaces (alloys 1199-H14 and 7075-T6) by solutions of Al(NO3)3, AlBr3, AlCl3, Al2' SO4)2, Al(ClO4)3, AlI3, and NaCl of various concentrations has been measured. Experiments were also conducted in saturated solutions of aluminum acetate, benzoate, phosphate, chromate and fluoride. The dissolution rate of the alloys varies considerably with the salt, the nitrate and iodide being most aggressive. The corrosion rate in sulfate solutions is much less than the rate in bromide, chloride, or perchlorate. The pH of the various salt solutions is not the determining parameter but for a given salt (AlCl) the corrosion rate increases with decrease in pH. The experiments definitely demonstrate that the activation effect is not restricted to aluminum chloride and suggests a strong chemical effect in the pitting and stress cracking mechanism. (Author)