The role and action mechanism of inhibitors in solutions for etching steel

Acid etching has a major task, regardless of which acid is used, to cancel all corrosion products from objects before it starts to erode base material. The effect of acid on base material causes metal and acid loss, as well as formation of etching defects. In order to prevent this undesired side effect, inhibitor is added in etching solution. In this paper we tested the inhibitory effect of three different inorganic inhibitors in HCl and H2SO4 solutions and one organic inhibitor in H3PO4 solution in the process of etching rust steel. The research was conducted using gravimetric method. Obtained results indicate protective value of inhibitor in over 98 % in all tested concentrations of HCl and H2SO4, while the inhibitory effect of organic inhibitor in H3PO4 solution at the temperture of 60ºC was absent.