A Ta-Nb alloy powder which has provides a capacitor having a higher capacitance than a Ta capacitor and a better thermal stability in terms of an oxide film is better than a Nb capacitor, the Ta-Nb alloy powder being a Ta-Nb alloy powder produced by a thermal CVD method, wherein a content of Nb is 1 to 50 mass %, and an average particle diameter of primary particles is 30 to 200 nm, preferably, a CV value per unit mass of the powder (μF.Math.V/g) is 250 kμF.Math.V/g or more, or further, a CV value per unit volume (μF.Math.V/mm.sup.3) in terms of a molded body whose molding density ρ (g/cm.sup.3) is ρ.sub.c (g/cm.sup.3)=−0.012R.sub.Nb+3.57, wherein R.sub.Nb: Nb content (mass %) in an alloy, is 900 μF.Math.V/mm.sup.3 or more, and an anode element for a solid electrolytic capacitor using the alloy powder.

A capacitor containing a solid electrolytic capacitor element including a sintered porous anode body and a relatively large diameter anode lead wire is provided. The lead wire is electrically connected to the anode body for connection to an anode termination. Further, the lead wire has a diameter that is at least about 10% of the height of the porous anode body to improve the points of contact between the anode body and wire to reduce ESR. A portion of the lead wire extends from a surface of the anode body in a longitudinal direction. At least one notch can be formed in the portion of the lead wire that extends from the anode body. The notch can be formed via a laser or by cutting, punching, or sawing and can serve as the point of electrical connection between the anode termination and the lead wire.

An improved solid electrolytic capacitor, and method of making the solid electrolytic capacitor, is described. The solid electrolytic capacitor comprises a pressed powder anode and a braided lead wire extending from the anode. A dielectric is on the anode and a cathode is on the dielectric.

A carbon paste including a carbon powder, a resin, and an oxygen releasing oxidizer. The amount of the oxidizer is 3 to 30 parts by mass based on 100 parts by mass of the total amount of the carbon powder and the resin. A solid electrolytic capacitor element is prepared by a method which includes making a valve-action metal powder sintered to obtain an anode body, electrolytically oxidizing a surface of the anode body to chemically convert the surface into a dielectric layer, electrolytic polymerization to form a semiconductor layer of an electro conductive polymer on the dielectric layer, applying the carbon paste onto the semiconductor layer, and drying and hardening the carbon paste to form a carbon layer.

A carbon paste including a carbon powder, a resin, and an oxygen releasing oxidizer. The amount of the oxidizer is 3 to 30 parts by mass based on 100 parts by mass of the total amount of the carbon powder and the resin. A solid electrolytic capacitor element is prepared by a method which includes making a valve-action metal powder sintered to obtain an anode body, electrolytically oxidizing a surface of the anode body to chemically convert the surface into a dielectric layer, electrolytic polymerization to form a semiconductor layer of an electro conductive polymer on the dielectric layer, applying the carbon paste onto the semiconductor layer, and drying and hardening the carbon paste to form a carbon layer.

The invention relates to the rare metal smelting field, and particularly, the present invention relates to a tantalum powder for preparing capacitors and a process for preparing the tantalum powder, and to a sintered anode prepared from the tantalum powder. As to the tantalum powder as provided by the invention, its primary tantalum powder has a BET of from 3.0 to 4.5 m.sup.2/g. After the secondary agglomeration, the tantalum powder has a large particle size. The tantalum powder has an average Fisher sub-sieve size (FSSS) of 1.2 to 3.0 μm wherein as measured with a standard sieve mesh, more than 75% of tantalum powder has a +325-mesh, and a particle size distribution D50 of more than 60 μm, that is, the secondary particle size is high. A resultant capacitor anode prepared by sintering the tantalum powder of the invention at 1200° C. for 20 minutes and then being energized at the voltage of 20 V has the specific capacitance of from 140,000 to 180,000 μFV/g and the residual current of less than 1.0 nA/μFV. Meantime, the invention provides an economical process for making the tantalum powder.

The invention relates to the rare metal smelting field, and particularly, the present invention relates to a tantalum powder for preparing capacitors and a process for preparing the tantalum powder, and to a sintered anode prepared from the tantalum powder. As to the tantalum powder as provided by the invention, its primary tantalum powder has a BET of from 3.0 to 4.5 m.sup.2/g. After the secondary agglomeration, the tantalum powder has a large particle size. The tantalum powder has an average Fisher sub-sieve size (FSSS) of 1.2 to 3.0 μm wherein as measured with a standard sieve mesh, more than 75% of tantalum powder has a +325-mesh, and a particle size distribution D50 of more than 60 μm, that is, the secondary particle size is high. A resultant capacitor anode prepared by sintering the tantalum powder of the invention at 1200° C. for 20 minutes and then being energized at the voltage of 20 V has the specific capacitance of from 140,000 to 180,000 μFV/g and the residual current of less than 1.0 nA/μFV. Meantime, the invention provides an economical process for making the tantalum powder.

An electrolytic capacitor includes an anode body having a porous structure, an anode lead having a sheet shape, a dielectric layer disposed on a surface of the anode body, a cathode layer covering at least a part of the dielectric layer, an anode lead frame electrically connected to the anode lead, and a cathode lead frame electrically connected to the cathode lead. The anode lead includes an embedded portion embedded in the anode body and a protrusion portion protruding to an outside of the anode body. The anode lead has a first main surface facing the cathode lead frame and a second main surface opposite to the first main surface. The anode lead is located between a center of the anode body and an end face of the anode body in a first direction in which the first main surface faces the cathode lead frame. The end face of the anode body is positioned at a side close to the cathode lead frame.

An electrolytic capacitor includes a capacitor element that includes an anode body that has a porous structure, a dielectric layer disposed on a surface of the anode body, and a solid electrolyte layer that covers at least a part of the dielectric layer. The anode body contains a first group metal including at least one selected from the group consisting of tantalum, niobium, titanium, aluminum, and zirconium. The dielectric layer contains an oxide of the first group metal and a second group metal including at least one selected from the group consisting of iron, chromium, copper, silicon, molybdenum, sodium, and nickel. A ratio X of a total number of atoms of the second group metal to a total number of atoms of the first group metal in the dielectric layer is equal to or less than 100 ppm.

An electrolytic capacitor includes a capacitor element that includes an anode body that has a porous structure, a dielectric layer disposed on a surface of the anode body, and a solid electrolyte layer that covers at least a part of the dielectric layer. The anode body contains a first group metal including at least one selected from the group consisting of tantalum, niobium, titanium, aluminum, and zirconium. The dielectric layer contains an oxide of the first group metal and a second group metal including at least one selected from the group consisting of iron, chromium, copper, silicon, molybdenum, sodium, and nickel. A ratio X of a total number of atoms of the second group metal to a total number of atoms of the first group metal in the dielectric layer is equal to or less than 100 ppm.