The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns. The present work focuses on the effect of cobalt content (0, 0.5 and 3.0) on the microstructural characteristics, melting point and corrosion performance of extruded Sn-9Zn solder alloys. The results reveal that the Zn-rich precipitates with spherical or needle-like shape in the Sn-9Zn-xCo alloys are refined remarkably by forming the γ-Co₅Zn₂₁ and Co₂Sn₂Zn Co-contained intermetallic compounds, though the melting point and eutectic reaction temperature decrease slightly. It is suggested that the corrosion property of the extruded Sn-9Zn-xCo alloys is improved significantly by adding the cobalt element, while the content should be controlled reasonably. Combining the corrosion morphology, the influence of cobalt content on the corrosion behavior of the Sn-9Zn-xCo alloys is analyzed in terms of the refined microstructure and the enhanced passive film stability.

由于对环境的关注，无铅焊料最近引起了广泛的关注。目前的工作集中在钴含量（0、0.5和3.0）对挤压的Sn-9Zn焊料合金的显微组织特性，熔点和腐蚀性能的影响。结果表明，尽管通过形成γ- Co ₅ Zn ₂₁和Co ₂ Sn ₂ Zn Co-金属间化合物，Sn-9Zn- x Co合金中的球形或针状富锌沉淀物得到了显着的细化。熔点和共晶反应温度略有降低。建议挤压Sn-9Zn- x的腐蚀性能通过添加钴元素可显着改善钴合金，同时应合理控制其含量。结合腐蚀形态，分析了钴含量对Sn-9Zn- x Co合金腐蚀行为的影响，从细化的微观结构和增强的钝化膜稳定性方面进行了分析。