Valve metal powders and process for producing them
AssigneeH. C. Starck GmbH
InventorsJosua Löffelholz, Hady Seyeda, Rüdiger Wolf, Karlheinz Reichert, Christoph Schnitter
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Abstract
Process for producing a valve metal powder by producing a precursor of desired morphology, converting the precursor into an oxide of the valve metal, stabilizing the structure of the oxide by heat treatment and reducing the stabilized oxide while retaining the morphology. Valve metal powders obtainable in this way, in particular comprising spherical agglomerates with a mean agglomerate size of 10–80 μm, preferably 20–40 μm, and use of these valve metal powders to produce solid electrolyte capacitors.
Claims14
A process for producing a valve metal powder, comprising the sequential steps of:
- a) producing a precursor of preformed morphology;
- b) converting the precursor into an oxide of the valve metal;
- c) stabilizing the morphology of the oxide by heat treatment;
- and
- d) reducing the stabilized oxide while retaining the morphology, thereby forming said valve metal powder,
- wherein, said precursor has a morphology comprising a primary structure, a secondary structure and a tertiary structure, and said valve metal powder has a morphology comprising a primary structure, a secondary structure and a tertiary structure,
- further wherein, said stabilization step is performed such that the secondary structure of said valve metal powder corresponds to the secondary structure of said precursor, and the tertiary structure of said valve metal powder corresponds to the tertiary structure of said precursor.
A process for producing a valve metal powder, comprising the sequential steps of:
- a) providing a precursor having preformed morphology, said precursor being an oxide of a valve metal;
- b) stabilizing the morphology of the oxide by heat treatment;
- and
- c) reducing the stabilized oxide while retaining the morphology, thereby forming said valve metal powder,
- wherein, said precursor has a morphology comprising a primary structure, a secondary structure and a tertiary structure, and said valve metal powder has a morphology comprising a primary structure, a secondary structure and a tertiary structure,
- further wherein, said stabilization step is performed such that the secondary structure of said valve metal powder corresponds to the secondary structure of said precursor, and the tertiary structure of said valve metal powder corresponds to the tertiary structure of said precursor.
Dependencies are inferred from the claim text.