A lead-free solder ball is provided which suppresses interfacial peeling in a bonding interface of a solder ball, fusion defects which develop between the solder ball and solder paste, and which can be used both with Ni electrodes plated with Au or the like and Cu electrodes having a water-soluble preflux applied atop Cu. The lead-free solder ball for electrodes of BGAs or CSPs consists of 1.6-2.9 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. It has excellent resistance to thermal fatigue and to drop impacts regardless of the type of electrodes of a printed circuit board to which it is bonded, which are Cu electrodes or Ni electrodes having Au plating or Au/Pd plating as surface treatment. The composition may include at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

A lead-free solder ball is provided which suppresses interfacial peeling in a bonding interface of a solder ball, fusion defects which develop between the solder ball and solder paste, and which can be used both with Ni electrodes plated with Au or the like and Cu electrodes having a water-soluble preflux applied atop Cu. The lead-free solder ball for electrodes of BGAs or CSPs consists of 1.6-2.9 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. It has excellent resistance to thermal fatigue and to drop impacts regardless of the type of electrodes of a printed circuit board to which it is bonded, which are Cu electrodes or Ni electrodes having Au plating or Au/Pd plating as surface treatment. The composition may include at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

In a solder alloy consisting essentially of tin, silver, copper, bismuth, antimony, indium, and nickel, the content ratio of the silver is 0.05 mass % or more and below 0.2 mass %; the content ratio of the copper is 0.1 mass % or more and 1 mass % or less; the content ratio of the bismuth is above 4.0 mass % and 10 mass % or less; the content ratio of the antimony is 0.005 mass % or more and 8 mass % or less; the content ratio of the indium is 0.005 mass % or more and 2 mass % or less; the content ratio of the nickel is 0.003 mass % or more and 0.4 mass % or less; and the content ratio of the tin is the remaining ratio and the mass ratio (Bi/Ni) of the bismuth content with respect to the nickel content is 35 or more and 1500 or less.

In a solder alloy consisting essentially of tin, silver, copper, bismuth, antimony, indium, and nickel, the content ratio of the silver is 0.05 mass % or more and below 0.2 mass %; the content ratio of the copper is 0.1 mass % or more and 1 mass % or less; the content ratio of the bismuth is above 4.0 mass % and 10 mass % or less; the content ratio of the antimony is 0.005 mass % or more and 8 mass % or less; the content ratio of the indium is 0.005 mass % or more and 2 mass % or less; the content ratio of the nickel is 0.003 mass % or more and 0.4 mass % or less; and the content ratio of the tin is the remaining ratio and the mass ratio (Bi/Ni) of the bismuth content with respect to the nickel content is 35 or more and 1500 or less.

An electrode, a preparation method therefor, and uses thereof. Titanium or titanium alloy is used as a base material of the electrode, the outer surface of the base material is coated with a composite material coating, and the composite material coating is prepared by coating a composite material solution and carrying out drying and sintering. The composite material solution is a nanoscale solution formed by dissolving transition metal elements in ethanol. The nanoscale solution is an ethanol solution of the nanoscale transition metal with particles of the transition metal as solutes thereof. The transition metal elements are platinum, iridium, ruthenium, gold, cerium, rhodium, tantalum, manganese, nickel, palladium, yttrium, gadolinium, cobalt, europium, lanthanum, neodymium, zirconium and titanium, and the molar ratio of the transition metal elements platinum, iridium, ruthenium, gold, cerium, rhodium, tantalum, manganese, nickel, palladium, yttrium, gadolinium, cobalt, europium, lanthanum, neodymium, zirconium and titanium in the composite material solution is 5-15:23-34:14-21:1-7:9-17:3-12:15-27:3-6:2-9:10-23:15-27:2-8:15-30:3-12:4-14:1-10:6-15:20-50.

An electrode, a preparation method therefor, and uses thereof. Titanium or titanium alloy is used as a base material of the electrode, the outer surface of the base material is coated with a composite material coating, and the composite material coating is prepared by coating a composite material solution and carrying out drying and sintering. The composite material solution is a nanoscale solution formed by dissolving transition metal elements in ethanol. The nanoscale solution is an ethanol solution of the nanoscale transition metal with particles of the transition metal as solutes thereof. The transition metal elements are platinum, iridium, ruthenium, gold, cerium, rhodium, tantalum, manganese, nickel, palladium, yttrium, gadolinium, cobalt, europium, lanthanum, neodymium, zirconium and titanium, and the molar ratio of the transition metal elements platinum, iridium, ruthenium, gold, cerium, rhodium, tantalum, manganese, nickel, palladium, yttrium, gadolinium, cobalt, europium, lanthanum, neodymium, zirconium and titanium in the composite material solution is 5-15:23-34:14-21:1-7:9-17:3-12:15-27:3-6:2-9:10-23:15-27:2-8:15-30:3-12:4-14:1-10:6-15:20-50.

The present invention provides a solder alloy, a solder paste, a solder ball, a resin flux-cored solder and a solder joint, both of which has the low-melting point to suppress the occurrence of the fusion failure, improves the ductility and the shear strength, and has excellent heat-cycle resistance. The solder alloy comprises an alloy composition composed of 35 to 68 mass % of Bi, 0.1 to 2.0 mass % of Sb, 0.01 to 0.10 mass % of Ni, and a balance of Sn. The alloy composition may contain at least one of Co, Ti, Al and Mn in total amount of 0.1 mass % or less. The solder alloy may be suitably used for a solder paste, a solder ball, a resin flux-cored solder and a solder joint.

A compound containing Sn, Te and Mn, and further containing either one or both of Sb and Bi.

A solder alloy has an alloy composition consisting of, in mass %, Ag: 0 to 4%, Cu: 0.1 to 1.0%, Ni: 0.01 to 0.3%, Sb: 5.1 to 7.5%, Bi: 0.1 to 4.5%, Co: 0.001 to 0.3%, P: 0.001 to 0.2%, and the balance being Sn.

A solder alloy has an alloy composition consisting of, in mass %, Ag: 0 to 4%, Cu: 0.1 to 1.0%, Ni: 0.01 to 0.3%, Sb: 5.1 to 7.5%, Bi: 0.1 to 4.5%, Co: 0.001 to 0.3%, P: 0.001 to 0.2%, and the balance being Sn.