Methods to at least partially reduce a niobium oxide are described wherein the process includes heat treating the niobium oxide in the presence of a getter material and in an atmosphere which permits the transfer of oxygen atoms from the niobium oxide to the getter material, and for a sufficient time and at a sufficient temperature to form an oxygen reduced niobium oxide. Niobium oxides and/or suboxides are also described as well as capacitors containing anodes made from the niobium oxides and suboxides.

Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides

Methods to at least partially reduce valve metal oxides are described wherein the process includes heat treating the valve metal oxide in the presence of a getter material, in an atmosphere which permits the transfer of oxygen atoms from the starting valve metal oxide to the getter material, and for a sufficient time and at a sufficient temperature to form an oxygen reduced valve metal oxide. Valve metal oxides and/or suboxides thereof are also described as well as capacitors containing anodes made from the valve metal oxides and suboxides thereof.

Methods to partially reduce certain metal oxides and oxygen reduced metal oxides

The invention relates a tantalum powder free of alkali and fluorine, which for a relatively small primary particle size has comparatively large secondary particles and is suitable for producing capacitors with a specific charge of between 100,000 and 180,000 μFV/g at specific residual currents of less than 2nA/μFV.

Tantalum powder, method for producing same powder and sintered anodes obtained from it

Pressed material such as anodes are described and formed from oxygen reduced oxide powders using additives, such as binders and/or lubricants. Methods to form the pressed material are also described, such as with the use of atomizing, spray drying, fluid bed processing, microencapsulation, and/or coacervation.

Modified oxygen reduced valve metal oxides

Metal powder Ta and/or Nb, with or without one or metals from the group Ta, Nb, Ti, Mo, W, V, Zr and Hf, is made in a fine powder form by reduction of metal oxide by contact with a gaseous reducing agent, preferably an alkaline earth metal, to near complete reduction, leaching, further deoxidation and agglomeration, the powder so produced being sinterable to capacitor anode form and processable to other usages.

Metal powders produced by the reduction of the oxides with gaseous magnesium

A flaked niobium powder is disclosed as well as electrolytic capacitors formed from the flaked niobium powders. Niobium powders having a BET surface area of at least about 0.50 m2/g are also disclosed and capacitors made therefrom, as well as niobium powders doped with an oxygen content of at least 2,000 ppm. Methods to reduce DC leakage in a niobium anode are also disclosed.

Niobium powders and niobium electrolytic capacitors

A process for sizing (i.e., comminuting) a tantalum powder including agglomerates of smaller particles, which process yields a tantalum powder having an as-comminuted agglomerate size distribution with the product of the Volume Mean Diameter, MV (in microns as measured by light scattering techniques such as Microtrac analysis), times specific surface area BET (m2/g), being less than about 25. These powders after sizing typically have ratios of Scott Bulk Density: BET Surface Area in the range from about 20 to about 35. Also provided are powders having a substantially unimodal and narrow agglomerate size distribution in all stages of production, namely after sizing (i.e., deagglomeration by comminution), thermal agglomeration (i.e., heat treatment), and deoxidation. These resultant powders have high surface area and good flowability properties and, upon sintering, exhibit controlled shrinkage with high porosity. Further provided are sized heat treated tantalum powders having agglomerate particle sizes wherein the product of the Volume Mean Diameter, MV, times the specific surface area, BET, is in the range from about 90 to about 250. Sized and agglomerated powders which are deoxidized are also provided wherein the product of the Volume Mean Diameter, MV, times the specific surface area, BET, is in the range from about 90 to about 250.

Method of making tantalum metal powder with controlled size distribution and products made therefrom

A capacitor having a central electrode body having sintered metal anode with an electrode lead, the anode having a sintered product produced from a tantalum powder having deagglomerated particles such that the product of the volume mean diameter in microns multiplied by the specific surface area measured in m 2 /g is a number in the range of below about 25. Capacitors having a central electrode with the anode produced from a sintered product produced from a heat treated and oxidized tantalum powder wherein the oxidized particle size is greater than about 0.7 m 2 /g. Capacitors are defined in terms of anodes produced from powders having specified ratios of Scott Bulk Density to surface area or ratio of die fill rate to surface area.

Tantalum metal power with controlled size distribution and products made therefrom

Verfahren zur herstellung von tantalpulver mit kontrollierter grössenverteilung sowie damit hergestellte formkörper

The present invention relates to a tantalum powder having substantially unimodal and narrow agglomerate size distribution, wherein the diameter of 10 percent of the agglomerate particles is less than 45 microns and the diameter of 90 percent of the agglomerate particles is less than 350 microns and the particles are defined by the following relationship 90 is less than or equal to [(MV) x (BET)] that is less than or equal to 250, wherein MV represents a Volume Mean Diameter (in microns as measured by light scattering techniques) and BET denotes specific surface area of the powder in me2/g. The specific surface area BET of the particles is greater than 0.7 me2/g. The invention also relates to a process for preparing the above-described tantalum powder as well as its use for producing capacitor anodes.

Steele Roger W

Papers

Niobium powders and niobium electrolytic capacitors

Method of making tantalum metal powder with controlled size distribution and products made therefrom

Tantalum metal power with controlled size distribution and products made therefrom

Verfahren zur herstellung von tantalpulver mit kontrollierter grössenverteilung sowie damit hergestellte formkörper

Tantalum powder, process for its preparation and use