Effect of Surface Microstructure Homogenization on Corrosion Behavior of ZQSn10-2 Tin Bronze Alloy Immersed in Seawater

For accelerated corrosion of δ precipitated phase area in ZQSn10-2 tin bronze surface microstructure, the surface uniformity of the material was improved through surface shot peening and annealing treatment. The effect of surface microstructure homogenization on the corrosion behaviour of the tin bronze was investigated. The microstructure and phase structure of the surface and cross-section of the tin bronze before and after seawater immersion corrosion were analyzed using scanning electron microscopy and X-ray diffraction. The results show that the microstructure of the cast tin bronze is composed of α matrix and δ phase, after homogenization treatment of shot peening and annealing, δ phase on the surface is almost eliminated. Under seawater immersion, the corrosion of the cast tin bronze is uneven, and the δ phase is preferentially corroded, with a serrated corrosion interface. The corrosion of the sample after homogenization treatment is uniform with a horizontal corrosion interface. The homogenization of material surface microstructure is beneficial for suppressing local corrosion.