Development of Representative Tests to Quantify the Susceptibility to Stress Corrosion Cracking of α,β'-Brass Used for Gas Transfer Devices

摘要

Corrosion susceptibility of an α,β'-brass CuZn40Pb2 (CW617N), used for gas transfer devices, was investigated through accelerated corrosion tests at a constant anodic potential in NaNO_3 solution with basic pHs. The anodic dissolution behavior of the α,β'-brass was characterized by a two stages-mechanism, with each stage including both dezincification and simultaneous dissolution phenomena of the β' phase but with different kinetics at each stage. Compressive or tensile stresses applied on brass specimens during the accelerated tests were observed largely to influence the anodic dissolution kinetics. Stresses were assumed to open or close the pores present in the dezincified β' phase, which promoted or slowed the dezincification mechanism, including with the Zn diffusion into the solution trapped inside of the pores.