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US 7,679,885 B2Granted
Tantalum powder and methods of manufacturing same
AssigneeCabot Corporation
InventorsYujiro Mizusaki, Hitoshi Iijima, Yoshikazu Noguchi
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AssigneeCabot Corporation
InventorsYujiro Mizusaki, Hitoshi Iijima, Yoshikazu Noguchi
Estimating the term…
Tantalum powder capable of providing a small-sized tantalum electrolytic capacitor while maintaining capacity is described. Tantalum powder in the present invention can be characterized in that the CV value is from 200,000 to 800,000 μFV/g, when measured by the following measuring method. Pellets are produced by forming tantalum powder such that the density is 4.5 g/cm3, then the pellets are chemically converted in a phosphoric acid aqueous solution of concentration 0.1 vol. % at a voltage of 6V and a current of 90 mA/g, and the chemically converted pellets are used as measuring samples to measure the CV value in a sulfuric acid aqueous solution of concentration 30.5 vol. % at a temperature of 25° C. under a frequency of 120 Hz and a voltage of 1.5V.
A tantalum powder, wherein when said tantalum powder is formed into an electrolytic capacitor anode, said anode has a capacitance of from 450,000 to 800,000 μFV/g, and is measured by pressing tantalum powder into pellets with tantalum lead wires, with a press density of 4.5 g/cm3, sintering said pellets, anodizing said sintered pellets in a phosphoric acid aqueous solution having a concentration of 0.1 vol. % under a voltage of 6V and a current of 90 mA/g to form anodized pellets and testing capacitance in a sulfuric acid aqueous solution having a concentration of 30.5 vol. % at a temperature of 25° C. under a frequency of 120 Hz and a voltage of 1.5V.
Dependencies are inferred from the claim text.