No Component Analysis And Development Of Halogen-free Solder Paste Flux

With the development of electronic-industry and surface mount technology(SMT), the solder paste has already become one of the most important electronic material in the primary device assembly of electronic-industry.The paper introduced the processes of SMT briefly and elementary knowledge about the solder paste in detail, such as definition, the function, the flux composition and so on.The experiment works had two parts:one was to analyze the composition of the halogen-free solder paste flux, the other was to prepare the halogen-free flux for lead-free solder paste. The results was as follows:(Ⅰ) The first part was to study the compositions of the halogen-free solder paster flux by using Gas Chromatography-Mass Spectrometry (GC-MS).The results were as follows:rosin acid, a acid, b acid, c acid were used as active ingredients; d,e, f were found; the corrosion inhibitor was benzotriazole.(Ⅱ) The second part,we took the value of spread rate as evluation criteria, studied the welding performance of the single active ingredient, found several active ingredients, two groups of complex organics as active agents were chosed. The orthogonal experiment was used to study each combination active ingredients performance and quantity effect relations. In accordance with the principle of solvent in flux,we chosed the organic alcohol and organic ether complex as solvent, studied the proportions of two components by orthogonal experiments. The paper researched the performance and quantities effect relations of several surface active ingredients, decided to select OP-10 for the flux. After a series tests of flux, the final outcome was as follows:the organic acid's proportion in solder paste flux was 5.5%, the surface active ingredients was 0.6%, solvent A:solvent B was 68:32, the rosin proportion was 40%. The lead-free solder paste flux had excellent soldering performance and without pollution.(Ⅲ) we tested the property of flux according to GB/T 9491-2002 standard, the spreading rate of lead-free solder paste was bigger than 80%, the surface insulation resistance (SIR) was over 1010,the acid value was about 200mg KOH/g and the physical property was stable.The result showed that the halogen-free flux had good wettability, excellent surface insulation resistance, no corrosion, halogen-free, environmental friendly and so on.(Ⅳ) A kind of lead-free solder paste flux was successfully developed. The flux matched with the lead-free solder powder for solder paste.We tested the spreading area, and contrasted with the import's solder paste.The result told us that:the flux property was good.