The invention provides a
tin alloy electroplating solution. The
tin alloy electroplating solution comprises organic mixed acid, organic
tin salt, organic
metal salt, complexing agents, reducing agents,
stabilizing agents, refining agents, brightening agents and deionized water. The tin
alloy electroplating solution comprises, by weight, 1000 parts of deionized water, 100-600 parts of organic mixedacid, 40-100 parts of organic tin salt, 1-8 parts of organic
metal salt, 50-160 parts of complexing agents, 30-70 parts of reducing agents, 20-100 parts of
stabilizing agents, 5-20 parts of refiningagents and 3-15 parts of brightening agents. The organic
metal salt comprises one of organic silver salt, organic
copper salt and organic
bismuth salt. The complexing agents comprise one or more of
thiourea, 1,3-dimethylthiourea, 2,4-dithiobiuret, 2,4,6-trithio-triuret, 2,2-dithiodipyridine, 2,2-dithio-
aniline, tetramethyl
guanidine, guanidinoacetic acid,
creatine monohydrate and sulphydryl
chitosan.