A lead-free solder alloy may comprise tin, silver, copper, bismuth, cobalt, titanium, and antimony. The alloy may further comprise antimony, nickel, or both. The silver may be present in an amount from about 3.1% to 3.8% by weight of the solder. The copper may be present in an amount from about 0.5% to 0.8% by weight of the solder. The bismuth may be present in an amount from about 0.0% (or 1.5%) to about 3.2% by weight of the solder. The cobalt may be present in an amount from about 0.03% to about 1.0% (or 0.05%) by weight of the solder. The titanium may be present in an amount from about 0.005% to about 0.02% by weight of the solder. The antimony may be present in an amount between about 1.0% to about 3.0% by weight of the solder. The balance of the solder is tin.

A bonding member that includes a resin body defining an airtight interior, and a bonding material enclosed in the interior of the resin body. The bonding material is a mixed powder that includes a plurality of particles of a first metal powder and a plurality of particles of a second metal powder. The second metal powder reacts with the first metal powder when melted to thereby produce an intermetallic compound. The resin body has a melting point higher than a softening point of the mixed powder.

A metal paste that includes a metal component and a flux. The metal component includes a first metal powder and a second metal powder. The first metal powder is Sn. The second metal powder is a CuNi alloy. The metal paste is heated for a time t1 to a temperature T1 where the first metal powder is melted. Next, the metal paste is heated for a time t2 longer than the time t1 at a temperature T2 lower than the temperature T1 to produce an intermetallic compound from the first metal Sn and the second metal CuNi alloy.

A flux containing an organic acid, a water-soluble base agent, and a solvent, but not containing water is adopted. In this flux, the organic acid includes 1,2,3-propanetricarboxylic acid. The water-soluble base agent is one or more selected from the group consisting of a nonionic surfactant and a weak cationic surfactant. The content of the 1,2,3-propanetricarboxylic acid is 1% by mass or more and 15% by mass or less with respect to the total amount of the entire flux, the total content of the water-soluble base agent is 30% by mass or more and 65% by mass or less with respect to the total amount of the entire flux, and the total content of the solvent is 30% by mass or more and 65% by mass or less with respect to the total amount of the entire flux. According to this flux, the wettability of solder can be enhanced and ball missing after reflow and flux residue washing is suppressed.

Undercooled liquid metallic core-shell particles, whose core is stable against solidification at ambient conditions, i.e. under near ambient temperature and pressure conditions, are used to join or repair metallic non-particulate components. The undercooled-shell particles in the form of nano-size or micro-size particles comprise an undercooled stable liquid metallic core encapsulated inside an outer shell, which can comprise an oxide or other stabilizer shell typically formed in-situ on the undercooled liquid metallic core. The shell is ruptured to release the liquid phase core material to join or repair a component(s).

An assembly for a dual-walled component of a gas turbine engine and methods of forming and repairing a dual-walled component. The assembly includes a cold section part having an outer surface that defines a plurality of impingement apertures, a hot section part including a pre-sintered preform, the hot section part positioned over the outer surface of the cold section part, and a plurality of support structures including the pre-sintered preform, the plurality of support structures positioned between the hot section part and the cold section part, the plurality of support structures separating the hot section part from the cold section part to define at least one cooling channel therebetween.

A method of furnace-less brazing of a substrate is provided. The method includes providing a substrate having a braze region thereon; disposing braze precursor material containing a nickel powder, an aluminum powder, and a platinum group metal powder on the braze region; and initiating an exothermic reaction of the braze precursor material such that the exothermic reaction produces a braze material that reaches a braze temperature above the solidus temperature of the braze material. A braze precursor material is also provided.

According to this invention, provided is a metal particle that includes an intermetallic compound composed of Sn, Cu and Ni, in a basal phase that contains Sn and an Sn—Cu alloy, and at least parts of the Sn—Cu alloy and the intermetallic compound in the basal phase form an endotaxial joint.

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 preformed solder including a lead-free solder mainly composed of Sn and a metal particle with a melting point higher than a melting point of the lead-free solder. The metal particle is formed of a Cu-Ni alloy having a Ni content of 0.1 to 90% by mass, or a Cu-Co alloy having a Co content of 0.1 to 90% by mass, and the lead-free solder may contain Ni when the metal particle is formed of the Cu-Ni alloy, or contains Ni when the metal particle is formed of the Cu-Co alloy, and (Cu,Ni) 6Sn5 is formed on a surface of the metal particle. With this preformed solder, a bonded portion having heat resistance, thermal conductivity, and reliability higher than ever can be formed.