Abstract: 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 KAlF4 and low in K3AlF6.

Abstract: A process for brazing of aluminium magnesium alloys is described applying a flux which comprises KAlF4 or CsAlF4 or both as major constituent. The flux further comprises at least one alkaline or alkaline earth metal compound selected from the group consisting of KAlF4, CsAlF4, Li3AlF6, CaF2, CaCO3, MgF2, MgCO3, SrF2, SrCO3, BaF2, and BaCO3. Preferably the flux comprises or consists of KAlF4, CsAlF4, and Li3AlF6 and optionally contains also BaF2.

Abstract: A process for brazing of aluminium magnesium alloys is described applying a flux which comprises KAlF4 or CsAlF4 or both as major constituent. The flux further comprises at least one alkaline or alkaline earth metal compound selected from the group consisting of KAlF4, CsAlF4, Li3AlF6, CaF2, CaCO3, MgF2, MgCO3, SrF2, SrCO3, BaF2, and BaCO3. Preferably the flux comprises or consists of KAlF4, CsAlF4, and Li3AlF6 and optionally contains also BaF2.

Abstract: 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 KAlF4 and low in K3AlF6.

Abstract: A process for brazing of aluminium magnesium alloys is described applying a flux which comprises KAlF4 or CsAlF4 or both as major constituent. The flux further comprises at least one alkaline or alkaline earth metal compound selected from the group consisting of KAlF4, CsAlF4, Li3AlF6, CaF2, CaCO3, MgF2, MgCO3, SrF2, SrCO3, BaF2, and BaCO3. Preferably the flux comprises or consists of KAlF4, CsAlF4, and Li3AlF6 and optionally contains also BaF2.

Abstract: Metal parts, especially parts made from aluminium, aluminium alloys, steel and stainless steel, are described which comprise a coating containing TiOF2 or titanyl hydroxyfluorides. The coating protects against corrosion. Titanium oxyfluoride and titanyl hydroxyfluorides in the form of a gel are also disclosed, as well as particulate Ti0.85O0.55(OH)1.1F1.2 having a specific particle size.

Abstract: Manganese tetrafluoride is prepared by a reaction between manganese difluoride or manganese trifluoride particles and elemental fluorine. During the reaction, surfaces of the particles are rendered fresh, e.g. by mechanical impact on the particles. Thereby, also agglomeration, sintering or vitrification of the particles is prevented. The impact is not so intensive that the particles would be crushed.

Abstract: The invention discloses nanoparticles which have preferably a particle size of less than 100 nm, have been coated with a dispersant, and optionally further comprise a crystallization inhibitor. Preferred dispersants are those which endow the nanoparticles with a hydrophilic or hydrophobic surface and contain reactive groups for coupling to or into polymers. Also disclosed are plastics comprising nanoparticles of this kind.

Abstract: The invention relates to noncorrosive auxiliaries for soldering aluminium and for upgrading aluminium alloys based on alkali metal fluoroaluminates, their preparation and their use. According to the invention, the noncorrosive auxiliaries contain metallates. To form the metallates, metal compounds of the elements of main groups 2 to 5 of the PTE or of the transition elements in the form of their salts or oxides are used as reactants. In particular, their halides, nitrates, carbonates, sulphates, phosphates, borates, hexafluorosilicates or oxides, for example, are used. According to the invention, the metal compounds are introduced into the reaction mixture of hydrofluoric acid and/or hydrated alumina and/or alkali metal compound, with the point in time when the metal compound is added being able to be varied as a function of the desired degree of functionalization of the surface.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Components made of aluminum and aluminum alloys can be brazed at temperatures of up to 600° 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.

Abstract: 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.

Abstract: 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.

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

Abstract: 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.