Chemical Components of Commercial Soldering Fluxes

Abstract

We have analysed the chemical components of sixteen commercial soldering fluxes using atomic absorption spectroscopy, spectrophotometry and X-ray diffractometry.We have examined the weight change in the fluxes with a thermobalance apparatus.The major elements were K, B, F in all fluxes and Na was a minor element.Small amounts of Al, Si, Cl were detected in three fluxes.Decrease in weight with the heating of the flux was probably a result of dehydration and evolution of CO₂.We have identified some of the chemical compounds such as KBF₄, KF, KCl, K₂CO₃, KHCO₃, K₂B₄O₇・4H₂O, KB₅O₈・4H₂O, K₂[B₃O₃(OH)F₄], K₂SiF₆, Na₂B₄O₇・5H₂O, H₃BO₃ in fluxes.One of the fluxes was amorphous.In conclusion, we found that commercial soldering fluxes consist of same limited number of elements and contain some materials well-known as chemical components of fluxes.