A flux applied in soldering to a substrate metal formed thereon with a firmly oxidized layer, the flux containing at least stannous chloride, non-oxidation acid and a viscous agent and excluding zinc chloride therefrom.
A non-zinc chloride type flux applied for use in plating a substrate metal member with molten tin, containing at least one chemical compound selected from the group of stannous chloride, sodium chloride, potassium chloride and ammonium chloride and excluding zinc chloride therefrom. The flux is floated on the surface of molten tin in the plating process or used in a condition of solution before the substrate metal member is plated with molten tin.
