ORGANIC CORROSION-INHIBITORS FOR ALUMINUM IN PERCHLORIC-ACID

Substituted N-arylpyrroles containing carbaldehyde groups on a pyrrole ring and their inhibitive effects on the corrosion of aluminum (Al) i n perchloric acid (HClO4) were investigated. Electrochemical measureme nts showed the organic compounds examined had good inhibiting properti es at 40 degrees C. The high inhibition effect of the N-aryl-2,5-dimet hylpyrroles containing carbaldehyde groups on a pyrrole ring on corros ion of Al in acid media was explained on the basis of the electronic s tructure of the molecule and by the condensation characteristic of the carbaldehydes. Investigation of the influence of substitution type (- F,-Cl, -NH2) on the inhibiting characteristics of examined organic com pounds showed the best inhibiting effect was from substituted N-arylpy rrole with fluorine in the ortho position of the phenyl ring.