Corrosion Inhibition of Aluminum Alloy AA6061 by CaSiO_3/PO_4 Based Pigments

摘要

A new corrosion inhibitor pigment system, based on defect substituted CaSiO_3/PO_4 is explored for Al alloy AA6061 in l%NaCl solution. DC polarization tests showed inhibition behavior comparable or exceeding chromate protection. The corrosion inhibition mechanism is understood to be due to mixed cathodic - anodic reactions. Adherent calcium hydroxyl, glassy silicate / phosphate films which forms on the substrate surface, significantly aided corrosion inhibition. The inhibition effect is confirmed by SEM analysis of the post-immersion metal surface, and revealed a diminishing pitting corrosion effects. With addition 0.1M gluconic acid to l%NaCl, the pigments exhibited enhanced cathodic and anodic inhibition. The effectiveness of inexpensive, non-toxic CaSiO_3/PO_4 pigments as corrosion inhibitors has been amply demonstrated in the study.