Sn_(62)Pb_(36)Ag_2焊料的微结构粗化  

MICROSTRUCTURE COARSENING OF Sn_(62)Pb/_(36)Ag_2 SOLDER

作　　者：叶润清[1] 罗乐[1] 

机构地区：[1]中国科学院上海冶金研究所,上海200050

出　　处：《功能材料与器件学报》1999年第4期327-331,共5页Journal of Functional Materials and Devices

摘　　要：在焊料的浸镀及表面贴装过程中，发现Ｓｎ６２Ｐｂ３６Ａｇ２ 焊料的微结构粗化，并且可焊性很差。金相研究发现：Ｓｎ６２Ｐｂ３６Ａｇ２ 合金焊料在熔体状态保温较长时间以及冷却速率较慢，均会促进焊料的微结构粗化。其机理为焊料中生成较多的Ａｇ３Ｓｎ 和Ｃｕ６Ｓｎ５ 等金属间化合物，消耗了合金焊料中的部分锡，使焊料组成偏离共晶点，从而最终导致富铅相偏析。组成偏离及微结构粗化致使焊料在铜上的润湿性降低，并影响焊料的可焊性。Microstructures of Sn 62 Pb 36 Ag 2 solders with different duration in molten state and cooling rate were investigated by metallographic analysis. Heterogeneous microstructure coarsening was found in the solder with slow cooling rate and/or longer duration. This phenomenon was attributed to the deviation of the composition of the composition of the solder from eutectic point due to depletion of tin resulted from the formation of intermetallic compounds such as Cu 6Sn 5 and Ag 3Sn. Heterogeneous microstructure coarsening can reduce the solderability of the solder.

关 键 词：SnPbAg焊料 焊接 相变 微结构 

分 类 号：TG425[金属学及工艺—焊接]