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 spreadabi lity 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

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... ned 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 NiC12, 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.