超声雾化Sn-Pb焊锡粉的组织特征及其抗氧化性能

采用定氧仪、扫描电镜和俄歇表面谱仪研究了超声雾化制备的Sn-Pb焊粉的氧化速率、组织与形貌特征，并与离心雾化焊粉进行了对比。结果表明：超声雾化法制备的粉末形貌和球形度明显优于离心雾化，但在大气中放置粉末的增氧速度较快。显微组织对比发现超声雾化制备的粉末组织晶粒细小、两相分布更加均匀；俄歇分析表明超声雾化粉末表面Pb出现一定程度的富集；高频振动和快冷促进了粉末组织的细化，表面富铅、晶界和相界数量增加是造成焊锡粉室温抗氧化性不足的主要原因。

Microstructure Characteristics and Oxidation Resistance of Sn-Pb Solder Powder Fabricated by Ultrasonic Atomization

The oxidation rate, microstructure and particle characteristics of Sn-Pb alloy solder powder fabricated by ultrasonic atomization and centrifugal atomization methods were examined. The results show that the appearance and sphericity degree for ultrasonic atomized powder is superior to centrifugal atomized powder, but the oxidation resistance is not enough. SEM observation shows that the microstructure of ultrasonic atomized powder is fine and uniform in distribution. The AES element analyzing indicates that Pb is rich in powder surface comparatively in ultrasonic atomization. High frequency vibration and fast solidification promote the formation of fine microstructure. Three factors including Pb rich in surface, the increasing in grain boundaries and phase boundaries were the main reasons to explain the oxidation mechanism.