International Standard Electric Corporation

Itt Industries, Inc.

Eric L Bush

Henley F Sterling

Denis William Hazelden

Ernest J Workman

John H Alexander

Miles P Drake

Sarah Y Hughes

Stephen J McManus

Ceramic capacitors are formed from electrodeposited ceramic dielectric layers that are provided with electrodes, stacked and fired. Contact to the electrodes is provided by each terminations and leads. As the electrodeposition process is self limiting and self heating, uniform pinhole free dielectric layers are obtained.

Capacitors

Powder which is too fine to be fluidized on its own is fluidized admixed with a sufficient quantity of coarser powder of a particle size that can be fluidized on its own. The process may be used for coating fine powders with valve-metal for the manufacture of capacitor electrodes.

Fluidizing fine powder

Powder is coated with valve-metal by rotating it in a drum 15 so that it is presented to valve-metal vapor derived by evaporation of a source of valve-metal. In the case of coating with aluminum, the vapor may be produced by directing aluminum wire 10 on to a heater 11, and oxygen or air is admitted to control agglomerate formation. Aluminum and tantalum coating are both described using electron beam evaporators.

Coating powder with valve-metal

A process for coating a particulate insulating material, e.g. alumina, with a uniform layer of a valve metal. The particles are exposed to a gaseous nitrogen compound, or to nitrogen gas together with hydrogen and a volatile halide of the valve metal. It is thought that nitrogen provides nucleation of the surface for subsequent metal deposition. The coated powder may be used in the fabrication of electrolytic capacitor anodes.

Coating powdered material

A solid electrolytic capacitor has a porous anode body manufactured from a valve metal coated core by pressure compaction of the metal powder at 25 to 40 tons per square inch. No subsequent sintering is required by this process.

Electrolytic capacitors

An electrolytic capacitor utilizes tantalum coated alumina particles as anode material to provide better breakdown properties than pure tantalum particles at a substantial savings in tantalum materials cost. The coating of valve metal having an anodized portion and an unanodized portion, the thickness of the unanodized portion not exeeding 0.5 microns.

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Matching Green, Near Harlow, United Kingdom

Eric L Bush