Studies on the Flux Action of Soldering (VI)

Flux Action of variour Silves Salts and Copper Salts on Ni and Fe Plates

Abstract

In previous paper, the flux action of various inorganic metal salts (chloride, sulfate and nitrate) for soldering was reported about the relation between the reaction of flux with molten Sn solder and spreadability of Sn solder on Cu plate.
In this report, authors have studied the relation between the reaction of base plate (Ni, Fe) or Sn solder with flux and spreading phenomenon of Sn solder on Fe plate or Ni plate in the case of various silver salts and copper salts as flux.
The results obtained were as follows:
(1) The corrosion rate increases from Ni, to Cu and to Fe.
(2) The effects of corrosion products on spreadability increased from FeCl₃, to FeCl₂, to NiCl₂, and to CuCl₂.
(3) FeSn₂ coated on Sn solder obstructs spreading of Sn solder.
(4) FeSn₂ produced by the reaction of molten Sn with Fe salt is controlled in proportion to the amount of Ag or Cu in Sn solder.
(5) Spreading of Sn solder on Fe plate is affected by FeSn₂ produced at interface of Sn solder and base plate.
(6) When Ni plate is used, Ni dissolves little in Sn solder and spreadability depends on the reactivity of Sn with flux.