The inhibition effects of chromate-free, anion inhibitors on corrosion of zinc in aerated 0.5 M NaCl

The inhibition effects of chromate-free, environmentally acceptable anion inhibitors were examined on corrosion of zinc in an aerated 0.5 M NaCl solution by polarization measurements, Sodium silicate Na2Si2O5 and phosphate Na3PO4 were remarkably effective on zinc corrosion, exhibiting high inhibition efficiencies around 90%. Fitting corrosion was not observed on the zinc electrode inhibited with these anions, The zinc surfaces treated with these anions in the solution were analyzed by X-ray photoelectron spectroscopy and electron-probe microanalysis. The inhibition efficiencies of molybdate MoO42- and tetraborate ions B4O(7)(2-) were not markedly high and phosphonates were less effective inhibitors. (C) 2001 Elsevier Science Ltd. All lights reserved.