Effect of halide ions on electrochemical behavior and stress corrosion cracking of 67/33 alpha-brass in aqueous environments

[[abstract]]The slow strain rate tension (SSRT) technique was used to study the effect of strain rate on susceptibility to stress corrosion cracking (SCC) and crack velocity of 67/33 alpha-brass (UNS C26800) in 0.1 M sodium halide solutions (pH = 6.8) at 25 degrees C. The effect of halide tons on electrochemical behavior of alpha-brass also was investigated using cyclic polarization techniques. Results indicated fluoride ions (F-) induced a significant susceptibility to intergranular stress corrosion cracking (IGSCC). Susceptibility increased with decreasing strain rate. Crack velocity also increased with strain rate in a double logarithmic relationship. The entire fracture surface was characteristic of IGSCC at a critical strain rate of 2 x 10(-6)/s. The open-circuit potential (OCP) was within the potential range where cuprous oxide (Cu2O) is stable. Electrochemical polarization analysis confirmed that 67/33 alpha-brass can form a passive Cu2O film in 0.1 M sodium fluoride (NaF) solution and that this passive film can break down. Results suggested film rupture and slip-dealloying dissolution may be involved in IGSCC of 67/33 alpha-brass in F- solution. In 0.1 M chloride (Cl-), bromide (Br-), or iodide (I-) solutions, no SCC susceptibility was observed regardless of strain rate. OCP moved to more active potentials in the presence of Cl-, Br-, and I-. This result was attributed to formation of soluble cuprous complexes controlling the dealloying process through precipitation of metal ion salts on the surface of alpha-brass.[[fileno]]2020334010054[[department]]材料