(北京工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，北京 100124)
摘 要: 將稀土相CeSn3與ErSn3暴露于空氣中，研究在時效處理過程中稀土相表面Sn晶須的形態(tài)機制。結(jié)果表明：時效過程中在稀土相表面出現(xiàn)的絕大多數(shù)Sn晶須均是具有恒定截面的規(guī)則Sn晶須；同時也發(fā)現(xiàn)少數(shù)特殊形態(tài)的不規(guī)則Sn晶須，如卷曲狀的Sn晶須、變截面的Sn晶須、分枝及搭接的Sn晶須等；由于稀土相的氧化所產(chǎn)生的體積膨脹提供Sn晶須生長的驅(qū)動力，而稀土相的氧化極不均勻，因此，認(rèn)為Sn晶須在生長過程中其根部受力狀態(tài)的改變是導(dǎo)致特殊形態(tài)Sn晶須出現(xiàn)的根本原因。
關(guān)鍵字: 無鉛釬料；稀土；Sn晶須；形態(tài)
（School of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China）
Abstract: The morphological mechanisms of tin whisker growth on the surface of oxidized CeSn3 and ErSn3 precipitates were investigated during the aging. The results indicate that most tin whiskers have constant cross section and regular shape. However, few irregular tin whiskers with special morphologies are also observed, including the spiral whiskers, whiskers with a non-constant cross section, branch-type whiskers and joining-type whiskers. Since the produced lattice expansion of the rare earth precipitates oxidization provides driving force for the tin whisker growth, and the oxidization is extremely uneven. Therefore, the changes of stress around the tin whisker root will primary cause that results in the growth of irregular tin whiskers.
Key words: lead-free solder; rare earth; tin whisker; morphology
