Abstract: Valve metal articles such as wire, sheet or powder having a second metal, preferably in a peripheral margin, prepared by coating the valve metal with a salt solution of the metal additive and heat treating in the presence of an oxygen getter to remove the oxygen from the valve metal and the anion of the metal salt to form the metal additive. For tantalum wire a preferred second metal is nickel. A preferred oxygen getter is magnesium. Nickel-containing tantalum wire is useful for enhance bonding to sintered pressed tantalum powder pellets in the production of electrolytic capacitors.

Abstract: A method for controlling oxygen in valve metal materials. The method includes deoxidizing a valve metal material, typically tantalum, niobium, or alloys thereof, and leaching the material in an acid leach solution at a temperature lower than room temperature. In one embodiment of the present invention, the acid leach solution is prepared and cooled to a temperature lower than room temperature prior to leaching the deoxidized valve metal material. The method of the present invention has been found to lower both the oxygen and fluoride concentrations in valve metal materials, as the use of reduced acid leach temperatures provide lower oxygen for a given quantity of a leach acid, such as hydrofluoric acid.

Abstract: An improved flaked tantalum powder and process for making the flaked powder are disclosed. The powder is characterized by having a Scott density greater than about 13 g/in.sup.3 and preferably at least about 90% of the flake particles having no dimension greater than about 55 micrometers. Agglomerates of the flaked tantalum powder, provide improved flowability, green strength and pressing characteristics compared to conventional flaked tantalum powders. The improved flaked tantalum powder can be made by preparing a flaked tantalum and then reducing the flake size until a Scott density greater than about 18 g/in.sup.3 is achieved. The invention also provides pellets and capacitors prepared from the above-described flaked tantalum powder.

Abstract: A method of making a tantalum capacitor of improved specific capacitance (and volumetric efficiency) is described. Short tantalum fibers are precipitated out of a carrier liquid to form a felt, or tumbled to form fiber containing particles, and in either case subsequently bonded so as to form a felt or particles containing the fibers in random orientation in substantially non-aligned array. These particles or felt are heated to bond the fibers together, purify and (optionally) cylindricalize them. The felt or particles can be processed in conventional fashion thereafter to form the capacitor. Cylindricalized fibers and pellets of increased surface area are also described.

Abstract: A method of making a tantalum capacitor of improved specific capacitance (and volumetric efficiency) is described. Short tantalum fibers are precipitated out of a carrier liquid to form a felt, or tumbled to form fiber containing particles, and in either case subsequently bonded so as to form a felt or particles containing the fibers in random orientation in substantially non-aligned array. These particles or felt are heated to bond the fibers together, purify and (optionally) cylindricalize them. The felt or particles can be processed in conventional fashion thereafter to form the capacitor. Cylindricalized fibers and pellets of increased surface area are also described.

Abstract: An improved flaked tantalum powder and process for making the flaked powder are disclosed. The powder is characterized by having a Scott density greater than about 18 g/in.sup.3 and preferably at least about 90% of the flake particles having no dimension greater than about 55 micrometers. Agglomerates of the flaked tantalum powder, provide improved flowability, green strength and pressing characteristics compared to conventional flaked tantalum powders. The improved flaked tantalum powder can be made by preparing a flaked tantalum and then reducing the flake size until a Scott density greater than about 18 g/in.sup.3 is achieved. The invention also provides pellets and capacitors prepared from the abovedescribed flaked tantalum powder.

Abstract: Tantalum electrode material is produced which has extremely low tortuosity, exceptionally low ESL and ESR, potentially extended high frequency performance, very high volumetric efficiency, and reduced tantalum consumption per electrode. The electrode material is characterized by having a cross-section composed of plates of tantalum separated by spaced gaps resulting in a highly dense (volumetric efficiency) electrode. The plates are electrically interconnected which also adds to the structural stability of the article. This is made possible by being able to carefully control the geometry of the tantalum material during processing. A method for producing such material includes extruding a billet filled with a (preferentially geometrically uniform) mixture of rods of tantalum and an extrudable metal. When the billet has been sufficiently reduced in size and severed, the extrudable metal is removed by selectively dissolving with acid.

Abstract: A method of making a tantalum capacitor of improved specific capacitance (and volumetric efficiency) is described. Short tantalum fibers are precipitated out of a carrier liquid to form a felt, or tumbled to form fiber containing particles, and in either case subsequently bonded so as to form a felt or particles containing the fibers in random orientation in substantially non-aligned array. These particles or felt are heated to bond the fibers together, purify and (optionally) cylindricalize them. The felt or particles can be processed in conventional fashion thereafter to form the capacitor. Cylindricalized fibers and pellets of increased surface area are also described.

Abstract: The invention relates to flaked tantalum powders suitable for use in electrodes and capacitors. The tantalum powders have a mean particle size of about 2 to 55 micrometers, a BET surface area greater than about 0.5 m.sup.2 /g, and an aspect ratio between about 2 and 50. The powders are in the form of fractured flakes, which contain substantially no tapering of their peripheral edges.

Abstract: A process for controlling the oxygen content in tantalum material comprising heating the material under a hydrogen-containing atmosphere in the presence of a getter composite comprising a getter metal encapsulated in tantalum.

Abstract: A process for controlling the oxygen content in tantalum material comprising heating the material under a hydrogen-containing atmosphere in the presence of a tantalum getter metal having an initial oxygen content lower than the tantalum material.

Abstract: A process for controlling the oxygen content in tantalum material comprising heating the material under a hydrogen-containing atmosphere in the presence of a getter composite comprising a getter metal encapsulated in tantalum.

Abstract: An improved flaked tantalum powder and process for making the flaked powder are disclosed. The powder is characterized by having a Scott density greater than about 18 g/in.sup.3 and preferably at least about 90% of the flake particles having no dimension greater than about 55 micrometers. Agglomerates of the flaked tantalum powder, provide improved flowability, green strength and presssing characteristics compared to conventional flaked tantalum powders. The improved flaked tantalum powder can be made by preparing a flaked tantalum and then reducing the flake size until a Scott density greater than about 18 g/in.sup.3 is achieved. The invention also provides pellets and capacitors prepared from the above-described flaked tantalum powder.

Abstract: A method for producing fiber-shaped tantalum powder by deforming a composite of tantalum powder and an auxiliary metal, and the powder produced thereby.