Abstract: A solder joint manufactured of an alloy essentially composed of 0.01-7.6 wt % Cu, 0.001-6 wt % Ni, and the remaining of Sn. Each of Cu and Ni has a maximum concentration range. The lower limit of the range of Ni is 0.01 wt % and preferably 0.03 wt %. The upper limit of the range of Ni is 0.3 wt % and preferably 0.1 wt %. The lower limit of the range of Cu is 0.1 wt % and preferably 0.2 wt %. The upper limit of the range of Cu is 7 wt % and preferably 0.92 wt %. The invention includes the solder joint essentially having these compositions.

Abstract: A method by which the amount of nickel contained in an alloy having a composition represented by Sn—X—Ni can be regulated. The method of nickel concentration regulation comprises adding phosphorus to Sn—X—Ni in a molten state (wherein X is one or more elements selected from the group consisting of Ag, Zn, Cu, Bi, Au, Ti, Ge, Ga, Si, and Ce), holding the mixture at 250-400° C., and removing the resultant dross floating on the surface of the liquid phase and containing a P—Ni compound and a P—Sn—Ni compound. An example of X is copper, and the content thereof may be 0.3-5 wt %. The phosphorus may be added in the state of a Sn—P alloy. The upper limit of the amount of the phosphorus to be added may be about half the nickel amount in terms of atomic amount.

Abstract: A granulation method for granulating a (CuX)6Sn5 compound by passing a composition comprising a (CuX)6Sn5 compound and tin through a multi-perforated plate to granulate the (CuX)6Sn5 compound wherein X represents an element which is solved in Cu but forms a precipitate with Sn.

Abstract: An apparatus for depositing and separating excess copper dissolved in molten lead-free solder containing tin as the main element is provided. An apparatus 1 deposits excess copper in the molten lead-free solder as an intermetallic compound and separates it from the molten solder. The apparatus includes a deposition bath 2 for causing an intermetallic compound in the molten solder, a metal added from the outside and copper in the molten solder to be deposited, a granulation bath 4 including plates 31 32 and 33 for allowing the molten solder to pass through the plates to merge the intermetallic compounds into particles having a larger diameter, and a separation bath 5 for causing the enlarged intermetallic compounds to precipitate and separate in the molten solder.

Abstract: Lead-free solder is replenished to a solder bath to receive a work having copper, the work to be processed subsequent to a soldering process using an air knife or a die. The replenished lead-free solder includes Sn as a major composition and at least 0.01 to 0.5 mass percent Ni. By replenishing the lead-free solder having the above composition, the density of the solder bath, being sharply changed for using one of a HASL device and a die, is quickly restored back to within an appropriate range.

Abstract: A solder joint manufactured of an alloy essentially composed of 0.01-7.6 wt % Cu, 0.001-6 wt % Ni, and the remaining of Sn. Each of Cu and Ni has a maximum concentration range. The lower limit of the range of Ni is 0.01 wt % and preferably 0.03 wt %. The upper limit of the range of Ni is 0.3 wt % and preferably 0.1 wt %. The lower limit of the range of Cu is 0.1 wt % and preferably 0.2 wt %. The upper limit of the range of Cu is 7 wt % and preferably 0.92 wt %. The invention includes the solder joint essentially having these compositions.

Abstract: Lead-free solder is replenished to a solder bath to receive a work having copper, the work to be processed subsequent to a soldering process using an air knife or a die. The replenished lead-free solder includes Sn as a major composition and at least 0.01 to 0.5 mass percent Ni. By replenishing the lead-free solder having the above composition, the density of the solder bath, being sharply changed for using one of a HASL device and a die, is quickly restored back to within an appropriate range.

Abstract: The purpose of the present invention is to separate excess coppers leached out in a lead-free solder bath and recover tin with high efficiency. An element X for forming a (CuX)6Sn5 compound between copper and tin in molten lead-free solders is added to separate out a (CuX)6Sn5 compound. Tin is recovered by binding the (CuX)6Sn5 compound by passing thereof through a multi-perforated plate, further generating swirling currents to precipitate and separate the bound (CuX)6Sn5 compounds and removing thereof.

Abstract: The purpose of the present invention is to separate excess coppers leached out in a lead-free solder bath and recover tin with high efficiency. An element X for forming a (CuX)6Sn5 compound between copper and tin in molten lead-free solders is added to separate out a (CuX)6Sn5 compound. Tin is recovered by binding the (CuX)6Sn5 compound by passing thereof through a multi-perforated plate, further generating swirling currents to precipitate and separate the bound (CuX)6Sn5 compounds and removing thereof.

Abstract: The purpose of the present invention is to separate excess coppers leached out in a lead-free solder bath and recover tin with high efficiency. An element X for forming a (CuX)6Sn5 compound between copper and tin in molten lead-free solders is added to separate out a (CuX)6Sn5 compound. Tin is recovered by binding the (CuX)6Sn5 compound by passing thereof through a multi-perforated plate, further generating swirling currents to precipitate and separate the bound (CuX)6Sn5 compounds and removing thereof.

Abstract: This method controls a copper density in a dip solder bath holding a molten solder alloy containing at least copper as an essential composition thereof during a dip soldering step of one of a printed circuit board with a surfaced copper foil and a component part having a copper lead attached thereto. The method includes a step of introducing a replenished solder containing no copper at all or a copper content having a density lower than that of the molten solder in the bath prior to the supply of the replenished solder to the bath so that the copper density in the bath is controlled to a predetermined constant density or lower. The molten solder alloy in the bath contains tin, copper and nickel as the major compositions thereof, and the replenished solder contains nickel and balanced tin, for example. Alternatively, the molten solder alloy in the bath contains tin, copper, and silver as the major components thereof, and the replenished solder contains silver and balanced tin.

Abstract: A lead-free solder characterized as comprising 0.1 to 2 wt % of Cu, 0.002 to 1 wt % of Ni with the residue being Sn. The solder preferably contains Cu in an amount of 0.3 to 0.7 wt %, and more preferably it contains Cu in an amount of 0.3 to 0.7 wt % and Ni in an amount of 0.04 to 0.1 wt %. The solder can be prepared by adding Ni to a molten mother alloy of Sn—Cu, or by adding Cu to a molten mother alloy of Sn—Ni. A lead-free solder which further comprises 0.001 to 1 wt % of Ga is also disclosed. The lead-free solder can form a solder joint having a high strength and stability comparable to those of a conventional Sn—Pb eutectic solder.

Abstract: A lead-free solder which is comprised of three elements Sn-Cu-Ni. Cu and Ni are 0.1-2 wt % and 0.002-1 wt % respectively. Preferable weight percentage of Cu and Ni are 0.3 to 0.7 percent and 0.04 to 0.1 percent respectively. Both methods of additive Ni to a base alloy of Sn—Cu and additive Cu to a base alloy of Sn—Ni are applicable.