Effect of corrosion inhibitor on corrosion inhibition performance of water-based environmental-friendly no-clean flux

A series of water based environmental-friendly fluxes were prepared with succinic acid and malic acid compounded (w=2.00%) as activator, glycol, isopropanol and ethylene glycol butyl ether compounded (w=3.00%) as co-solvent, polyethylene glycol 6000 (w=0.25%) as film-forming reagent, and imidazole (IM), benzimidazole (BIA), benzotriazole (BTA) as corrosion inhibitor respectively. The corrosion inhibition performance of imidazole, benzimidazole, benzotriazole on the copper in the flux was investigated with the static weight-loss method, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Corrosion inhibition efficiency increased firstly with the increase of concentration of inhibitor, but decreased over the optimum concentration. With 0.08% benzotriazole as inhibitor, the inhibiting rate was up to 88.78%, metal film resistance Rf was up to 1.25 × 106 Ω · cm2, and the flux showed better corrosion inhibition. The research also indicated that inhibiting rate was up to 94.25% and Rf was up to 2.26 × 106 Ω · cm2, when the content of the compounded inhibitor remained as 0.08% and the mass ratio of BIA and BTA was 1:1 in the flux. These results indicated that there was a good synergistic effect after BIA and BTA compounded as inhibitor. A tight absorbed protective film was formed after the addition of compounded corrosion inhibitors together, which might be the main reason that inhibited and reduced copper corrosion. The data of spreading area of flux also indicated that the suitable amount of compounded corrosion inhibitors was 0.04% BIA and 0.04% BTA. © All Rights Reserved.