Stainless steels resist corrosion through formation of an oxygen-rich passive film. Halide ions damage this film and promote localized attack. Chloride ions are the most prevalent halide ions in our environment and are involved in many stainless steel corrosion failures. Bromine compounds have many important technological uses and localized corrosion caused by bromide ions is a significant problem, but one that has been less studied. The types and uses of bromides include lithium bromide for absorption refrigeration, volatile bromine compounds concentrated during thermal desalination of seawater, zinc bromide in heavy drilling fluids, bromine compounds used as less oxidizing disinfectants in spas and pools, and bromide feeds for FGD mercury control. Titanium is very resistant to chloride containing environments.
However, it can corrode via pitting in bromide containing solutions depending on conditions. In many cases the bromides are present alongside chlorides. Reliable corrosion data is needed to support materials selection and process design for such environments. Experiments were conducted to determine the critical pitting temperature of several alloys (S31603, S32003, S32205, N08367, S32760, N06110, N06022, N10276 alloys and Grade 2 titanium) in calcium bromide solutions using the ASTM G150 electrochemical critical pitting test procedures. Similar experiments were also conducted in solutions containing equal concentrations (by weight) of chlorides and bromide. Corrosion of S32003, N08367, Grade 1 titanium and other alloys in LiBr solutions was studied. The results of these experiments are described in this paper.
Bromides, Stainless Steel, S32003, S32205, N08367, S32760, N06110, N06022, N10276, Grade 2 titanium, Pitting Corrosion, Crevice Corrosion