Greatbatch Ltd.

Wilson Greatbatch Technologies, Inc.

David Goad

Barry C Muffoletto

Yanming Liu

Neal N Nesselbeck

Jason T Hahl

Janson Hahl

A method and apparatus for anodizing a porous valve metal pellet in a flowing liquid electrolyte is described. The apparatus comprises an insulative container comprised of a lower region, a central region including a cavity for holding the pellet, an upper region, and a continuous passageway extending through the lower, central, and upper regions. Lower and upper screens serving as lower and upper electrodes are disposed in the passageway in the lower and upper container regions, respectively. During anodizing, the electrolyte flows through the lower container region including the lower screen, the porous pellet and then the upper container region including the upper screen. The lower and upper screens are at an opposite electrical polarity as the pellet so that a dielectric oxide is formed on the exposed valve metal including interior portions of the pellet that are exposed to the flowing electrolyte.

Valve metal anode pellets for capacitors formed using forced convection of liquid electrolyte during anodization

Method of forming valve metal anode pellets for capacitors using forced convection of liquid electrolyte during anodization

A method for anodizing valve metal structures to a target formation voltage is described. The valve metal structures are placed in an anodizing electrolyte and connected to a power supply that generates a source voltage to at least one current limiting device. If at least two current limiting devices are used, they are in series with the valve metal structures with the one current limiting device connected to at least one structure. The valve metal structures are then subjected to a current that decreases over time, a formation voltage that increases over time to a level below the voltage from the power supply and a power level that is self-adjusted to a level that decreases excessive heating in the structure. The invention also includes the components for the method.

Anodizing valve metals by self-adjusted current and power

An oxygen plasma process for treating a dielectric oxide layer, particularly an anodic oxide, subsequent to its incorporation into an electrolytic capacitor is described. The present treatment reduces DC leakage and improves shelf life stability of the resulting capacitor in comparison to anodic oxides treated in a conventional manner. This is important for critical applications such as implantable cardioverter defibrillators where capacitor charging time and charge/discharge energy efficiency are critical.

Plasma treatment of anodic oxides for electrolytic capacitors

A sintering method for valve metal powders, such as tantalum, niobium, aluminum, titanium, and their alloys, is described. The valve metal powders are pressed into a pellet and sintered at a relatively high temperature, but for a relatively short time. The anodized valve metal structure is then useful as an anode in an electrolytic capacitor.

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Buffalo, NY, United States of America

David Goad