Effect of H3BO3 on corrosion in 0.01 M NaCl solution of the interface between low alloy steel A508 and alloy 52 M

• The pits in A508 are stopped immediately by adding H3BO3 in NaCl solution.
• No obvious Cl− enrichment exists in the pit after adding H3BO3 in NaCl solution.
• Element B is enriched in the pit after adding H3BO3 in NaCl solution.

The corrosion of the low alloy steel A508-alloy 52 M interface region in buffered and non-buffered chloride containing solutions was studied by using the scanning vibrating electrode technique (SVET), scanning ion-selective electrode technique (SIET), and time of flight secondary ion mass spectroscopy (ToF-SIMS). The typical pit in low alloy steel A508 formed in NaCl solution was stopped immediately when H3BO3 was added to the NaCl solution, and the pit became cathodic. With increasing immersion time, H3BO3 entered into the pit, and the corrosion of A508 became general corrosion.