A conductive paste and method of manufacturing thereof. The conductive paste comprises conductive particles dispersed in an organic medium, the organic medium comprising: (a) a solvent; and (b) a binder comprising a polyester. The conductive paste typically comprises silver and may contain various other additives. A stretchable conductive layer can be formed by curing the conductive paste.

Invention compositions are a replacement for high melting temperature solder pastes and preforms in high operating temperature and step-soldering applications. In the use of the invention, a mixture of metallic powders reacts below 350 degrees C. to form a dense metallic joint that does not remelt at the original process temperature.

Provided is a metal paste for joints, containing: metal particles; and linear or branched monovalent aliphatic alcohol having 1 to 20 carbon atoms, in which the metal particles include sub-micro copper particles having a volume average particle diameter of 0.12 μm to 0.8 μM.

A solder alloy, a solder powder and the like, which suppresses change in a solder paste over time and has excellent wettability, a small temperature difference between the liquidus temperature and the solidus temperature, and excellent mechanical properties, and exhibits a high joint strength, are provided. The solder alloy has an alloy composition containing 0.55 to 0.75 mass % of Cu, 0.0350 to 0.0600 mass % of Ni, 0.0035 to 0.0200 mass % of Ge, and 25 to 300 mass ppm of As, at least either one of 0 to 3000 mass ppm of Sb, 0 to 10000 mass ppm of Bi, and 0 to 5100 mass ppm of Pb, and a balance of Sn, and satisfies Expressions (1) to (3) below.

275≤2As+Sb+Bi+Pb  (1)

0.01≤(2As+Sb)/(Bi+Pb)≤10.00  (2)

10.83≤Cu/Ni≤18.57  (3)

In Expressions (1) to (3) shown above, Cu, Ni, As, Sb, Bi, and Pb each represent an amount (mass ppm) in the alloy composition.

By using a solder paste including powder of a lead-free solder alloy mainly composed of Sn and a metal particle with a melting point higher than a melting point of the lead-free solder alloy, in which the metal particle is formed. of a Cu—Ni alloy having a Ni content of 0.1 to 90% by mass, or formed of a Cu—Co alloy having a Co content of 0.1 to 90% by mass, a solder bonded body that has heat resistance, thermal conductivity, and reliability higher than ever can be formed.

Provided is flux that can achieve a low residue so as to make it possible to ensure solder wettability, ensure holding properties of a solder ball, and suppress the amount of residue after soldering and enable application for use without washing. The flux includes 1-15% by weight of an organic acid mixture comprising an organic acid with 10 or more carbon atoms, 50-90% by weight of isobornyl cyclohexanol, and 5-45% by weight of a different solvent. The proportion of the isobornyl cyclohexanol is 50-95% by weight, where 100% by weight is the total of the isobornyl cyclohexanol and the different solvent. The organic acid mixture comprising the organic acid with 10 or more carbon atoms comprises 2-methylnonanedioic acid, 4-(methoxycarbonyl)-2,4-dimethylundecanedioic acid, 4,6-bis(methoxycarbonyl)-2,4,6-trimethyldecanedioic acid, and 8,9-bis(methoxycarbonyl)-8,9-dimethylhexadecanedioic acid.

A method for joining a first metal part with a second metal part, the metal parts having a solidus temperature above 1100° C., includes applying a melting depressant composition on a surface of the first metal part, the melting depressant composition including a melting depressant component that includes at least 25 wt % boron and silicon for decreasing a melting temperature of the first metal part; bringing the second metal part into contact with the melting depressant composition at a contact point on said surface; heating the first and second metal parts to a temperature above 1100° C.; and allowing a melted metal layer of the first metal component to solidify, such that a joint is obtained at the contact point. The boron at least partly originates from a boron compound selected from any of the following compounds: boric acid, borax, titanium diboride and boron nitride. The melting depressant composition and related products are also described.

A soldering method in which abrasive particles, in particular cubic boron nitride, are applied in a matrix composed of a solder material and are intended to have better adhesion in the matrix material. The particle which includes an abrasive particle, in particular of cubic boron nitride, is coated with a metal. A method for producing a layer on a substrate, wherein a solder material is applied as metallic matrix material such with particles, in particular solder material in the form of a soldering paste, a soldering tape, a solder powder, by an application method, in particular by a welding process or a thermal spraying process.

A ceramic-copper composite having a flat plate shape, including: a ceramic layer; a copper layer; and a brazing material layer present between the ceramic layer and the copper layer, in which a specified Expression (1) is satisfied in a cut surface of the copper layer obtained when the ceramic-copper composite is cut at a plane perpendicular to a main surface of the ceramic-copper composite, where S(102)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (102) plane is within 10°, S(101)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (101) plane is within 10°, S(111)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (111) plane is within 10°, and S(112)% is an area ratio occupied by copper crystals having a crystal orientation of which an inclination from a crystal orientation of (112) plane is within 10°.

Provided are a flux composition that is applicable without any film formation step, and solder paste, a solder joint and a solder joining method using the flux composition. The flux composition contains 20 wt % or more and 50 wt % or less of an epoxy resin, 15 wt % or more and 45 wt % or less of diallyl bisphenol A, and 1 wt % or more and 30 wt % or less of organic acid.