Solvay Fluor Und Derivate Gmbh

Solvay Sa

Solvay Pharmaceuticals, Gmbh

Solvay Fluor and Derivative Gmbh

Solvay Fluor Gmbh

Ulrich Seseke-Koyro

Werner Rudolph

Stefan Palsherm

Andreas Becker

Andreas Grossmann

Thomas Born

Alf Schulz

Placido Garcia-Juan

Joachim Frehse

The invention concerns a flux for brazing, a process for brazing metal parts employing said flux, a flux composition containing said flux, aluminum parts coated with said flux or said flux composition, a process for brazing and a brazed metal object obtainable by said brazing process. The flux is high in KAlFand low in KAlF.

Flux for brazing

A process for brazing of aluminium magnesium alloys is described applying a flux which comprises KAlFor CsAlFor both as major constituent. The flux further comprises at least one alkaline or alkaline earth metal compound selected from the group consisting of KAlF, CsAlF, LiAlF, CaF, CaCO, MgF, MgCO, SrF, SrCO, BaF, and BaCO. Preferably the flux comprises or consists of KAlF, CsAlF, and LiAlFand optionally contains also BaF.

Process for brazing of aluminum alloys and a flux

Fluxing agents comprising potassium fluorostannate and/or cesium fluorostannate which can be used for brazing or soldering components of aluminum or of an aluminum alloy, even by solderless brazing or soldering. Conventional fluxing agents or other fluorometallates, such as alkali metal fluorozincates and/or alkali metal fluorosilicates, can also be added to the fluorostannate-containing fluxing agent. The fluxing agents of the invention can be applied by either dry or wet fluxing methods.

Fluorostannate-containing brazing or soldering fluxes and use thereof in brazing or soldering aluminum or aluminum alloys

Novel methods for producing alkali metal fluorozincates, especially potassium fluorozincate. Products having defined particle size ranges are obtained depending on the sequence of introduction of the reactants alkali metal hydroxide, zinc oxide and hydrogen fluoride. The resulting alkali metal fluorozincates are particularly suitable for use as a fluxing agent or fluxing agent additive during brazing of aluminum or aluminum alloys and can be applied by wet or dry fluxing methods depending on the particle size of the alkali metal fluorozincate particles.

Alkali metal fluorozincate and method for producing it

Components composed of aluminum or an aluminum alloy with a coating comprising an aluminum-silicon alloy deposited thereon by applying an alkali metal fluorosilicate and heating the resulting treated material. The alloy layer is effectively protected against re-oxidation by a non-corrosive, alkali metal fluoroaluminate layer (e.g. a potassium fluoroaluminate layer) which forms simultaneously.

Components coated with an aluminum-silicon alloy

Components made of aluminum and aluminum alloys can be brazed at temperatures of up to 600&deg; C. using a fluxing agent composed of alkali fluorozincate or alkali fluoride/zinc fluoride mixtures. Other fluxing agents, for example those composed of potassium fluoroaluminate can be used in addition. Alkali fluorozincate fluxing agents, especially potassium and cesium fluorozincate fluxing agents, act not only as a fluxing agent but also improve the surface quality since zinc and alkali fluoroaluminates are deposited on the surface of the components. The invention also relates to new fluxing agents containing alkali metal fluorozincates.

Fluxing agents

Flux residues from aluminium soldering fluxes composed of alkali metal metallates, especially fluoroaluminates of the alkali metals, in particular potassium and cesium, can be recycled by adding them to the reaction mixture used for the production of hydrogen fluoride from fluorspar and sulfuric acid or oleum. In this way the fluorine content of the flux residues becomes reusable, and the anhydrite which is produced can advantageously be used for conventional purposes.

Recycling of flux material

A process for removing water and/or carbon compounds from hydrogen fluoride by contacting the hydrogen fluoride to be purified with elemental fluorine.

Removal of water and/or hydrocarbons from hydrogen fluoride

A process for preparing ultrapure hydrogen fluoride by contacting impure hydrogen fluoride with elemental fluorine in the presence of metal fluorides. The ultrapure hydrogen fluoride which can be obtained can be used in electronics or optics or for preparing fluorine-containing organic or inorganic compounds or ultrapure hydrofluoric acid.

Growing community of inventors

Isernhagen, Germany

Ulrich Seseke-Koyro