Corrosion Behavior of Alloy A3003 After Brazing in HCl, CH3COOH, and Mixed Solutions

Dip and dry corrosion tests were carried out on Alloy A3003 (UNS A93003) using hydrochloric acid (HCl), acetic acid (CH3COOH), and a mixed solution. After 50 corrosion test cycles with the HCl solution, pitting corrosion occurred in some parts at higher concentrations, but corrosion weight loss was very low. In the case of the CH3COOH solution, general corrosion occurred, thickness decreased, and weight loss significantly increased as the concentration grew. In the case of the mixed solution, both general corrosion and pitting corrosion occurred, and corrosion mass loss increased as the HCl concentration grew. Also, in concentrations of more than 50 ppm of HCl, the number of pits significantly increased. Electrochemical polarization measurements were done to understand the corrosion forms for each acid. In the electrochemical polarization, the pitting potential became less noble with increasing concentration of HCl. No distinct effect of CH3COOH on the pitting potential was confirmed, but corrosion current density increased with increasing concentration of CH3COOH. For the mixed solution, both of these effects were confirmed. These electrochemical polarization results correspond well with the dip and dry corrosion test results.