The dual pretreatment of phytate-molybdate for corrosion resistance of carbon steel in simulated concrete pore solution

Abstract

In this study, phytic acid conversion film and molybdate corrosion inhibitor were combined using the dual pretreatment method. The main purpose was to make up for the deterioration of corrosion resistance caused by the cracking of the phytic acid conversion film. Electrochemical analysis showed the corrosion resistance of the dual pretreatment was increased by 99.0% and 102.3% respectively compared with the single phytic acid and molybdate pretreatment. In addition, the rapid corrosion initiation time was 96 h and 108 h later than that of single phytic acid and molybdate pretreatment, respectively. The corrosion protection mechanism of dual pretreatment was investigated by means of morphology and composition analysis. Phytic acid and iron substrate were combined by chelating, and molybdate corrosion inhibitor reacts with iron substrate to form Fe2(MoO4)3/FeMoO4 through phytic acid film cracks to form corrosion protection, which showed excellent synergistic effect. On the one hand, the dual pretreatment makes up for the shortcomings caused by cracks in the phytic acid conversion film itself, and on the other hand, it also reduces the amount of corrosion inhibitor by using the pretreatment method, and effectively avoiding the problems of difficult migration and easy leakage of corrosion inhibitor.