Inhibierung der Lochbildung und des Lochwachstums bei Aluminium

Inhibition of pit initiation and pit growth on aluminum Under potentiostatic conditions over 40 organic and inorganic compounds have been investigated in order to determine their inhibiting effect on the pitting corrosion of aluminum in 0.01 molar NaC1 solutions. The concentration dependent inhibitor efficiency decreases in the order: Na-oleate, NO ? WO > IO, MoO, BrO, Na-benzoate > CrO > NO, Na-tartrate. SO, ClO and the other organic compounds tested accelerate the pit growth as well as too low concentrations of inhibiting ions. The accelerating effect depends directly on the conductivity of the electrolyte. The inhibitor efficiency depends on the potential and is deteriorated by non inhibiting ions such as ClO or SO. The minimum concentration required to inhibit completely the pit initiation and the pit growth is often not identical. This fact explains partly the inconsistent data found in the literature. The phenomena observed are explained on the basis of the Temkin isotherm.