The present invention relates to paste compositions comprising an indium metal powder; and an organic vehicle. The organic vehicle includes one or more C8-C18 fatty acids; a salt formed from a C4-C6 carboxylic acid and a tertiary alkanolamine; a cationic catalyst; a thixotrope; and a diluent.

An approach to provide an electronic assembly process that includes receiving at least one electronic assembly after a solder reflow process using a Sn-containing solder and a water-soluble flux. The approach includes baking the at least one electronic assembly in an oxygen containing environment and, then cleaning the at least one electronic assembly in an aqueous cleaning process.

Solder paste consisting of 85 to 92% by weight of a tin-based solder and 8 to 15% by weight of a flux, wherein the flux comprises i) 30 to 50% by weight, based on its total weight, of a combination of at least two optionally modified natural resins, ii) 5 to 20% by weight, based on its total weight, of at least one low-molecular carboxylic acid; and iii) 0.4 to 10% by weight, based on its total weight, of at least one amine, and wherein the combination of the optionally modified natural resins has an integral molecular weight distribution of 45 to 70% by area in the molecular weight range of 150 to 550 and of 30 to 55% by area in the molecular weight range of >550 to 10,000 in the combined GPC.

A flux according to the present invention includes a phosphine oxide. It is thereby possible to provide a flux capable of improving solder wettability, a resin flux cored solder including the flux, and a solder paste including the flux.

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).

A lead-free solder material is provided. In one example, the solder material may include solder particles including at least 30 wt % nickel, and an activator including or consisting of at least one of a group of activator materials, the group including an organic acid or salt thereof, and an amine or salt thereof.

A solder composition contains: a flux composition containing an (A) rosin resin, a (B) activator, a (C) thixotropic agent, and a (D) solvent; and (E) solder powder, in which the (B) component contains a (B1) dicarboxylic acid having 3 to 8 carbon atoms, the (C) component contains at least one selected from the group consisting of a (C1) amide thixotropic agent having a hydroxy group in one molecule and a (C2) glycerol thixotropic agent having a hydroxy group in one molecule, and the solder composition satisfies a condition represented by Numerical Formula (F1) below provided that a total of contents of the (C1) component and the (C2) component is defined as X and a content of the (B1) component is defined as Y,

[00001]$\text{X}\text{}/\text{}2\le \text{Y}\le 5\text{X}$

A flux containing an organic acid, an acrylic resin, a rosin, a thixotropic agent, and a solvent, but not containing water is adopted. In this flux, the organic acid includes 1,2,3-propanetricarboxylic acid, and the content of the 1,2,3-propanetricarboxylic acid is 0.1% by mass or more and 15% 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, temperature cycle reliability is excellent, and scattering due to heating during reflow can be suppressed.

A solder paste is adopted, the solder paste containing: a solder alloy powder in which a content of solder alloy particles having a particle size of 8 μm or less is 99% by mass or more with respect to a total mass of the solder alloy powder; and a flux. This flux contains an acid-modified rosin, a solvent, an activator, and a thixotropic agent, in which the activator contains a halogenated aliphatic compound, and a dicarboxylic acid represented by General Formula (2).

##STR00001##

[in the formula, R represents an alkylene group having 1 to 7 carbon atoms, or a single bond, provided that a methylene group constituting the alkylene group may be substituted with an oxygen atom]

Compositions and methods for coupling metals to aluminum surfaces are provided. The compositions are prepared as aqueous solutions or suspensions, and can be applied to the aluminum surface using conventional printing techniques. Rheology of the printable composition can be adjusted to provide a gel or a cream. Curing steps, if necessary, are performed at low temperatures that are compatible with plastic/polymer components of mass produced devices, such as aluminum RFID antennae.