A brazing paste contain 80% by mass or more and 95% by mass or less of a brazing material; and 5% by mass or more and 20% by mass or less of a binder. The binder contains a solid solvent containing two or more hydroxyl groups and having 5 to 7 carbon atoms, and a liquid solvent.

A metal particle aggregate includes metal particles and an organic substance. The metal particles include first particles that contain one or both of silver and copper in an amount of 70% by mass or more relative to 100% by mass of all metals and have a particle diameter of 100 nm or more and less than 500 nm at a ratio of 20 to 30% by number, and include second particles that have a particle diameter of 50 nm or more and less than 100 nm, and third particles that have a particle diameter of less than 50 nm at a ratio of 80 to 70% by number in total. Surfaces of the first to third particles are covered with the same protective film.

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.

The present invention uses a flux containing a rosin, a solvent, a thixo agent, and an activator. The thixo agent contains a polyamide and a compound represented by general formula (1). The polyamide is a condensate between an amine and at least one selected from aliphatic carboxylic acids and hydroxy group-containing aliphatic carboxylic acids, and has an endothermic peak at a temperature of 120-200° C. In the general formula, R.sup.11 represents a hydrocarbon group having 11-30 carbon atoms. R.sup.0a represents a hydrogen atom or a hydrocarbon group having 12-31 carbon atoms. R.sup.0b represents an n-valent hydrocarbon group having 4-12 carbon atoms. R.sup.21 represents an alkylene group having 2-6 carbon atoms. R.sup.0c represents a single bond or an alkylene group having 2-6 carbon atoms. n represents 1 or 2. When n represents 1, m represents an integer of 1-3. When n represents 2, m represents 1.

##STR00001##

A method of using an amalgamation preform includes providing mating bonding surfaces and placing a particle-liquid mixture corresponding to the amalgamation preform between the mating bonding surfaces. The particle-liquid mixture contains a plurality of types of solid particles and a base metal in a liquid form, and the plurality of types of solid particles at least includes reactive particles reactable with the base metal and non-reactive magnetic particles. A first magnetic field is applied to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid base metal to form a particle-liquid dispersion; and a second magnetic field is applied to cure the particle-liquid dispersion to allow reactions between the reactive particles and the base metal.

A solder alloy is provided which can withstand the severe characteristics of a temperature cycle between a low temperature of −40° C. and a high temperature of 125° C., withstand an external force applied due to, for example, riding on a curb or collision with a vehicle ahead for a long period of time, and can suppress change in viscosity of a solder paste over time. In addition, a solder paste, a solder ball, and a solder preform in which the solder alloy is used; a solder joint formed through the use thereof; and an on-board electronic circuit, an ECU electronic circuit, an on-board electronic circuit device, and an ECU electronic circuit device which include this solder joint are provided. The solder alloy contains, by mass %, 1% to 4% of Ag, 0.5% to 1.0% of Cu, 1.5% to 5.5% of Bi, 1.0% to 5.3% of Sb (or greater than 5.5% and less than or equal to 7.0% of Bi and 2.0% to 5.3% of Sb), 0.01% to 0.2% of Ni, 0.0040% to 0.0250% of As, and a balance of Sn.

Disclosed is a braze putty composition including a sacrificial binder, a first nickel alloy and a second nickel alloy, a method of making the putty, and a method for using this putty to repair castings.

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.

Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.

An amalgamation preform is provided. The amalgamation preform includes a base metal, and a plurality of types of solid particles dispersed in the base metal, the base metal including one of a liquid base metal and a solid base metal. The plurality of types of solid particles at least includes: non-reactive magnetic particles, responsive to a magnetic field for controllably dispersing the plurality of types of solid particles in the base metal, and reactive particles, reactable with the base metal under the magnetic field.