Corrosion behavior of tin‐phosphor bronze strips in environments containing Cl− and HCO3−

Abstract

AbstractThe corrosion behaviors of Cu–7.42Sn–0.156P and Cu–5.78Sn–0.162P alloys in different solutions were investigated. The results show that the Cu–Sn–P alloy with higher Sn content exhibits better corrosion resistance. In the NaCl, NaHCO3, and NaCl+NaHCO3 solutions, compared with Cu–5.78Sn–0.162P alloy, the corrosion current densities of Cu–7.42Sn–0.156P alloy are reduced by 25.2%, 36.9%, and 34.5%, and the polarization resistances are increased by 32.0%, 25.4%, and 29.9%. The Cu–Sn–P alloys have the best corrosion resistance in the NaHCO3 solution, followed by the NaCl solution and the worst in the NaCl + NaHCO3 solution. The increase of Sn is helpful to improve the density and spalling resistance of the corrosion film. There is a double‐layer structure for the corrosion film of Cu–Sn–P alloy. For the alloys immersed in the NaCl solution and the NaCl+NaHCO3 solutions, the corrosion films consisted of Cu2O, CuO, and SnO2. For the alloys immersed in the NaHCO3 solution, the corrosion films are composed of Cu2O, CuO, SnO, and SnO2. The increase of Sn content in the alloy can increase the contents of Cu2O and SnO in the corrosion films.