Th. Goldschmidt Ag

Goldschmidt Ag

Frank Honselmann

Dieter Guhl

Joachim Giersberg

Dirk Naumann

Jan Eberhardt

The invention relates to an aqueous preparation for the pickling and activation of aluminum-steel composites prior to electroless dip tinning. Specifically, the invention provides pickling/activation solutions for the pretreatment of aluminum-steel composites prior to dip tinning which comprise sulfuric acid, hexafluorosilicic acid, at least one wetting agent, at least one transition metal cation and nitrate and/or nitrite ions.

Pickling/activation solution for the pretreatment of aluminum-steel composites prior to dip tinning

Acidic electrolyte for dip-tin-plating aluminum alloys, containing tin salts, surfactants and additives yielding halogen ions, fluorine complexes, having the optimum effective halogen content that corresponds to its maximum solubility, being added as additives yielding halogen ions.

Self-regulating, acidic electrolytes for dip-tin-plating aluminum alloys

The invention provides a process for preparing bismuth compounds, in particular a process for preparing highly concentrated solutions of bismuth methanesulfonate, that are stable to hydrolysis. The preparation takes place from aqueous solutions of bismuth compounds of the formula (I)

Process for preparing bismuth compounds

A method is disclosed for the preparation of finely divided, electrically conductive tin(IV) oxide. In a first step tin(IV) oxalate and/or oxalates of polymeric tin(IV) compounds are obtained by electrolysis, in which the anode consists of tin or a tin alloy which contains a doping metal, and the cathode consists of a metal or graphite. The two electrodes are separated by a diaphragm or an organic membrane which is permeable to hydrogen ions and oxalic acid solution is used as electrolyte. Tin(IV) oxide is prepared in the second step by calcining the oxalates obtained from the solution of tin(IV) oxalate and/or oxalates of polymeric tin(IV) compounds, to which known doping agents have been added in conventional amounts.

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Weingarten, Germany

Frank Honselmann