A method of forming an electrolytic capacitor is provided. The method includes obtaining an unverified mineral sample from a mine site, analyzing the unverified mineral sample via quantitative mineralogical analysis and comparing data collected during the quantitative mineralogical analysis for the unverified mineral sample to data in a database that corresponds to quantitative mineralogical analysis collected for verified mineral samples sourced from one or more mine sites from a conflict-free geographic region to determine if the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region. If it is determined that the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region, the method then involves converting the unverified mineral sample into an anode for the electrolytic capacitor. The electrolytic capacitor can be a solid electrolytic capacitor or a wet electrolytic capacitor.

A capacitor assembly that is capable of performing well under the conditions of high humidity (e.g., 60% relative humidity) is provided. The capacitor assembly comprises a solid electrolytic capacitor element that contains a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. An anode termination is in electrical connection with the anode body and a cathode termination is in electrical connection with the solid electrolyte. A first coating is disposed on at least a portion of the anode termination that contains an organometallic compound and a second coating is disposed on at least a portion of the cathode termination that contains an organometallic compound. Further, a casing material encapsulates the capacitor element and leaves exposed a mounting surface of the anode termination and the cathode termination.

An aluminum electrode in which a porous layer made of a sintered layer of aluminum powder having an average particle diameter of 1 m to 10 m is laminated in a thickness of 150 m to 3000 m on a surface of an aluminum core material is produced by chemical formation to produce an anode for an electrolytic capacitor. In this process, an organic acid immersion step of immersing the aluminum electrode in an organic acid aqueous solution containing dodecanoic acid, benzoic acid, propanedioic acid, butanedioic acid, (E)-2-butenedioic acid, 2-hydroxypropane-1,2,3-tricarboxylic acid, (E)-1-propene-1,2,3-tricarboxylic acid, or the like is carried out after a pure water boiling step and before a chemical formation step. In the chemical formation step, a phosphoric acid immersion step of immersing the aluminum electrode in an aqueous solution containing phosphate ions is carried out one or more times in the course of raising a film withstand voltage to a chemical formation voltage.

A method of producing metallic tantalum comprises the steps of providing a precursor comprising a tantalate of a first metal, arranging the precursor material in contact with a molten salt in an electrolytic cell, the electrolysis cell further comprising an anode and a cathode arranged in contact with the molten salt, and applying a potential between the anode and the cathode such that the precursor material is reduced to tantalum. The first metal is an alkali metal or an alkaline earth metal. The anode does not comprise a carbon material, which prevents contamination of the tantalum and improves current efficiency of the process.

A capacitor that includes a conductive base material with high specific surface area, a dielectric layer covering the conductive base material with high specific surface area, and an upper electrode covering the dielectric layer, in which the conductive base material with high specific surface area is formed of a metal sintered body as a whole.

A method of forming an electrolytic capacitor is provided. The method includes obtaining an unverified mineral sample from a mine site, analyzing the unverified mineral sample via quantitative mineralogical analysis and comparing data collected during the quantitative mineralogical analysis for the unverified mineral sample to data in a database that corresponds to quantitative mineralogical analysis collected for verified mineral samples sourced from one or more mine sites from a conflict-free geographic region to determine if the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region. If it is determined that the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region, the method then involves converting the unverified mineral sample into an anode for the electrolytic capacitor. The electrolytic capacitor can be a solid electrolytic capacitor or a wet electrolytic capacitor.

An electrode holder and a method for producing an electrode for an aluminum electrolytic capacitor are provided that enable prevention of exfoliation of a porous layer during chemical formation even when the porous layer is formed on an aluminum electrode so as to have a thickness of 200 micrometers or greater. When an aluminum electrode 10 having at least one surface 11 on which a porous layer 17 having a thickness of 200 micrometers or greater is formed is subjected to chemical formation in a chemical formation solution, the aluminum electrode 10 is held by an electrode holder 50. The electrode holder 50 includes: an insulating first support plate 51 configured to overlap the one surface 11 of the aluminum electrode 10; an insulating second support plate 52 configured to overlap the other surface 12 of the aluminum electrode 10; and a connecting part 53 configured to connect the first support plate 51 and the second support plate 52 to each other. A portion of the first support plate 51 that overlaps the porous layer 17 while being in contact therewith is formed with a porous member 510.

A stereostructure includes a core portion, and a porous portion located around the core portion. The porous portion located inside a position which is inside from an outer edge of the porous portion by 3/20 of a diameter of the stereostructure in an arbitrary cross section of the stereostructure has a void ratio per unit area of less than or equal to 80%.

A solid electrolytic capacitor containing a capacitor element is provided. The capacitor element contains a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. An anode lead extends from the front surface of the capacitor element in the longitudinal direction. An anode termination is in contact with the anode lead at a connection region, wherein the ratio of the distance between the connection region and the front surface of the capacitor element to the length of the capacitor is 0.13 or more. A cathode termination is in electrical connection with the solid electrolyte and a casing material encapsulates the capacitor element and anode lead. Further, an interfacial coating that is disposed on at least a portion of the anode termination and/or cathode termination and is in contact with the casing material.

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 m 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 m, 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 FV/g and the residual current of less than 1.0 nA/FV. Meantime, the invention provides an economical process for making the tantalum powder.