Composite metal as a contact material for vacuum switches
AssigneeSiemens Aktiengesellschaft
InventorsHeinrich Hassler, Horst Kippenberg, Horst Schreiner
Life of this patent
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Abstract
A contact material for vacuum switches comprising a composite inclusion metal of at least two metal components in which a first component has an electric conductivity of at least 10 m/ohm mm.sup.2, the share of this component being between 35 and 60% by volume. At least one component has a melting point of at least 1400.degree. C and at least one component is effective as a getter. These components are embedded in the first component, with only isolated bridges existing between the finely distributed inclusions. The porosity of the composite inclusion metal is less than 2% by volume.
Claims11
A composite inclusion metal for vacuum switches comprising a mixture of copper as a first metal component in an amount from about 35% to 60% by volume of said composite inclusion metal, a second metal component selected from the group consisting of iron and nickel and a getter component selected from the group consisting of chromium, titanium and zirconium;
- wherein at least one of said second or getter components is embedded in said copper to form a heterogeneous microstructure with only isolated bridge formations existing between finely-distributed inclusions, said composite inclusion metal being formed by cold-pressing a mixture of said copper, said second metal component and said getter component to form a molding with a porosity of less than 30% by volume, sintering the molding at a temperature below the melting point of the lowest melting component of said mixture in a protective gas or vacuum, and hot-densifying the molding at a temperature below the melting point of the lowest melting component down to a residual porosity of less than 2% by volume.
A composite inclusion metal for vacuum switches comprising a mixture of copper or nickel as a first component in an amount of from 35 to 60% by volume of said composite, a second metal component consisting of aluminum wherein said second component is embedded in said first component to form a heterogeneous microstructure with only isolated bridge formations existing between finely-distributed inclusions, said composite inclusion metal being formed by cold-pressing a mixture of said components to form a molding with a porosity of less than 30% by volume, sintering the molding at a temperature below the melting point of the lowest-melting component of said mixture in a protective gas or vacuum and hot densifying the molding at a temperature below the melting point of the lowest-melting component down to a residual porosity of less than 2% by volume.
A composite inclusion metal of a mixture of copper and chromium wherein said copper is present in an amount of from 35 to 60% by volume, said chromium being embedded in said copper to form a heterogeneous microstructure with only isolated bridge formations existing between finely-distributed inclusions, said composite inclusion metal being prepared by mixing the copper and chromium in powder form, cold-pressing the mixture to form a molding with a porosity of less than 30% by volume, sintering the molding in a protective gas or vacuum, the sintering temperature being in the range of from above the melting temperature of said copper to a temperature not exceeding 100.degree. C. above said melting temperature, and hot densifying the molding at a temperature below the melting point of the copper down to a residual porosity of less than 2% by volume.
Dependencies are inferred from the claim text.