PROBLEM: To provide a multi-layer preform sheet capable of forming a highly reliable and high-quality electric interconnect, an electro-conductive bonding portion and so forth that are less likely to produce the Kirkendall void.

SOLUTION: A multi-layer preform sheet having at least a first layer and a second layer, the first layer being composed of a solder material that contains an intermetallic compound, and the second layer containing a first metal having a melting point of 300° C. or above, and a second metal capable of forming an intermetallic compound with the first metal.

The present disclosure generally relates to the field of tin electroplating. More specifically, the present disclosure relates to methods for mitigating tin whisker formation on tin-plated films and tin-plated surfaces by doping the tin with germanium.

Provided is a tin-plated copper terminal material, a terminal formed from the terminal material, and an electric-wire terminal structure using the terminal: the terminal material has a substrate of copper or a copper alloy; an intermediate zinc layer of a zinc alloy that is formed on the substrate and has a thickness of 0.10 μm to 5.00 μm; and a tin layer of tin or a tin alloy that is formed on the intermediate zinc layer and in which the length proportion occupied by low-angle grain boundaries is 2% to 30% with respect to the total length of all crystal grain boundaries; wherein galvanic corrosion is effectively suppressed.

A tin-plated copper alloy terminal material in which an Sn-based surface layer is formed on a surface of a base material that is made of copper or a copper alloy, and a Cu—Sn alloy layer and an Ni layer or an Ni alloy layer are sequentially formed between the Sn-based surface layer and the base material from the Sn-based surface layer side: the Cu—Sn alloy layer is a layer that is formed only of an intermetallic compound alloy which is obtained by substituting some of Cu in Cu.sub.6Sn.sub.5 alloy with Ni; and parts of the Cu—Sn alloy layer are exposed from the Sn-based surface layer, thereby forming a plurality of exposed portions; an average thickness of the Sn-based surface layer is from 0.2 μm to 0.6 μm (inclusive); and an area rate of the exposed portions of the Cu—Sn alloy layer relative to a surface area of is 1% to 40% (inclusive).

The present invention provides a titanium copper foil having improved adhesion to solder and higher resistance to discoloration due to a high temperature and high humidity environment, an acid solution or an alkaline solution, and as well as having improved etching processability. The present invention provides a titanium copper foil comprising a base metal, the base metal having a composition containing Ti of from 1.5 to 5.0% by mass, the balance being copper and inevitable impurities, and having a thickness of from 0.018 to 0.1 mm, wherein the titanium copper foil has an Sn plated layer on a surface of the base metal, and has an adhesive strength of 0.5 N or more as measured by a solder adhesive strength test according to the definition in the specification.

An electroconductive material includes a Cu or Cu alloy base member, a Cu—Sn alloy coating layer, and a Sn coating layer. The Cu—Sn alloy coating layer has a Cu content of 20 to 70 atomic %, and an average thickness of 0.2 to 3.0 μm. The Sn coating layer has an average thickness of 0.2 to 5.0 μm. A surface of the electroconductive material has an arithmetic average roughness Ra of at least 0.15 μm in at least one direction along the surface and 3.0 μm or less in all directions along the surface. The Cu—Sn alloy coating layer is partially exposed at the surface of the electroconductive material. An area ratio of the Cu—Sn alloy coating layer exposed at the surface of the electroconductive material is 3 to 75%. An average crystal grain size on a surface of the Cu—Sn alloy coating layer is less than 2 μm.

In various embodiments, electronic devices such as touch-panel displays incorporate interconnects featuring a conductor layer and, disposed above the conductor layer, a capping layer comprising an alloy of Cu and one or more refractory metal elements selected from the group consisting of Ta, Nb, Mo, W, Zr, Hf, Re, Os, Ru, Rh, Ti, V, Cr, and Ni.

A wiring board and a method for manufacturing the wiring board in which an initial Cu plated layer is formed by plating so as to cover the surface of a metallized layer and then the initial Cu plated layer is heated to be softened or melted. Copper in the softened or melted initial Cu plated layer enters into open pore portions of the metallized layer. In addition, during the heating, components of the metallized layer and components of the initial Cu plated layer are mutually thermally diffused. Consequently, when solidified later (that is, when the initial Cu plated layer becomes a lower Cu plated layer), the adhesiveness between the metallized layer and the lower Cu plated layer is improved due to, for example, an anchoring effect and a mutual thermal diffusion effect.

A hot-dip Sn—Zn-based alloy-plated steel sheet according to an aspect of the present invention includes: a steel sheet having a predetermined chemical composition; a diffusion alloy layer provided on one surface or both surfaces of the steel sheet; and a Sn—Zn-plated layer provided on the diffusion alloy layer, in which the diffusion alloy layer contains Fe, Sn, Zn, Cr, and Ni, an area ratio of a Sn—Fe—Cr—Zn phase to a Sn—Fe—Ni—Zn phase in the diffusion alloy layer is 0.01 or more and less than 2.5, the diffusion alloy layer has a coverage of 98% or more with respect to the one surface, the Sn—Zn-plated layer contains 1% to 20% of Zn by mass % and a remainder consisting of Sn and impurities, and an adhesion amount of the Sn—Zn-plated layer is 10 to 80 g/m.sup.2 per one surface.

An electrical connector includes a first layer formed of a copper based material and a second layer formed of an iron-nickel alloy. The second layer has a thickness of 8% to 30% of the thickness of the electrical connector. The electrical connector also includes a third layer which is formed of a solder alloy that consists essentially of 17% to 28% indium by weight, 12% to 20% zinc by weight, 1% to 6% silver by weight, 1% to 3% copper by weight, and a remaining weight of the solder alloy that is tin.