Siemens Aktiengesellschaft

Th. Goldschmidt Ag

Martin Edeling

Konrad Mund

Helmut Freller

Michael Steinhorst

Erhard Weidlich

Horst Eggert

Peter Schack

Ulrich Gebhardt

Raghavendra Rao

A method for producing single-phase intermetallic phases, which melt incongruently within a temperature range of 900.degree. to 2,000.degree. K., with a homogeneity range of .ltoreq.10 atom % at room temperature by co-reduction is described. The exothermic reaction of the calciothermal reduction is adjusted by altering the oxide content of the reaction mixture, the composition of which corresponds to the desired single-phase alloy, in such a way that the temperature condition T.sub.m &gt;T.sub.R .gtoreq.0.9 T.sub.m (in .degree. K.) is fulfilled, T.sub.m being the melting temperature of the intermetallic phase and T.sub.R the reaction temperature. The components of the reaction mixture, with the exception of calcium, have an average particle size of .ltoreq.75 .mu.m. The reaction product at the end of the exothermic reaction is tempered at a temperature which is at least 0.7 times the melting temperature T.sub.m of the desired, single-phase alloy, measured in .degree. K., but is less than the melting temperature T.sub.m, during a period sufficient for the diffusion of the components.

Method for producing single-phase, incongruently melting intermetallic

In a method for manufacturing an implantable electrode, particularly a stimulating electrode, vitreous carbon is sputtered from a vitreous carbon target on at least a part of the surface of the electrode. The sputtering is performed in an argon atmosphere at a pressure of 4 to 8.times.10.sup.-2 mbar and at a voltage of 1.6 to 2.4 kV. The electrode may consist essentially of platinum-iridium, vitreous carbon or platinum.

Method for the fabrication of an implantable electrode

The invention relates to a method for the manufacture of implantable electrodes of vitreous carbon with an electrode head and an electrode stem, by pyrolysis of cross-linked synthetic resins. Electrodes manufactured in accordance with such a method exhibit high surface quality. In accordance with embodiments of the disclosure, the electrode stem is manufactured in the form of a blank by hardening a resin precondensate, then the electrode head is cast onto the blank in a casting mold, using a resin precondensate, and is cross-linked. Subsequently hardening takes place and then the synthetic resin is converted into vitreous carbon by pyrolysis, and the electrode obtained in this manner may, if desired, be activated to provide the electrode with a microporous surface structure.

Method for the manufacture of implantable electrodes of vitreous carbon

Porous vitreous carbon with good electrical and mechanical properties as well as large double-layer capacitance can be produced by hardening and pyrolysis of thermosetting carbonizable resins including about 1 to 10 weight-percent of a salt of a fatty acid having about 10 to 20 carbon atoms which is soluble in the resin and can be volatilized without residue.

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Essen, Germany

Martin Edeling