The effects of rare earth Ce on the microstructure and shear properties of SnAgCu solder were investigated in this paper.The microstructure and fracture morphologies were measured by SEM,the components of alloy were analyzed by EDS,and the mechanical properties of solder joints were tested by mechanical test enginery.The results show that,when the 0.25wt.% Ce was added,the β-Sn phase and Ag3Sn phase in the microstructure were refined,and small amounts of Sn-Ce phases and partial gathering areas of Ce were observed;After reflowing with the solder paste prepared from gas-atomized powder,the microstructure of solder joints matrix was refined with Ce addition.The oxygen contents of solder powders increased because Ce was tend to surface enrichment and oxidation after gas-atomization,and the holes near the IMC layer were increased after reflowing,so the shear strength of solder joints decreased.%研究了稀土Ce对Sn-3.0Ag-0.5Cu合金显微组织及焊点剪切强度的影响规律.利用扫描电镜对铸态合金及焊点显微组织和断口形貌进行了观察和分析,利用能谱仪对铸态合金组分进行测试,采用力学试验机测试焊点的剪切强度.研究表明：当Ce添加量为0.25%时,铸态合金显微组织中β-Sn相与Ag3Sn相明显细化,出现了少量的Sn-Ce相及Ce的偏聚区;采用气雾化粉末所配制的焊膏进行回流焊,添加Ce后,焊点基体组织比未添加时明显优化;经过气雾化制粉,Ce向粉末表面富集并极易氧化,导致焊粉氧含量升高,使得回流焊接后焊料/Cu界面IMC层附近孔洞增加,焊点剪切强度降低.
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