Sprague Electric Company

Manuel Finkelstein

Sidney D Ross

Franz S Dunkl

Franz C Dunkl

John E Barry

A phthalate electrolyte containing benzil provides aluminum electrolytic capacitors having low equivalent series resistance and low rates of change in equivalent series resistance with time on voltage.

Low resistivity low ESR capacitor electrolyte

A filtered solution of barium hydroxide octahydrate reacted with an aqueous solution of boric acid to provide hydrated .gamma. barium borate having a barium to boron ratio of 1:2 and having fine particle size. The hydrated .gamma. barium borate was converted to the anhydrous .gamma. form at about 300.degree. to 400.degree. C. Further heating to about 600.degree. to 800.degree. C. converted the product to .beta.-BaB.sub.2 O.sub.4. The conversion to the .beta.-form is preferably during sintering of a ceramic dielectric composition to which the .gamma.-BaB.sub.2 O.sub.4 has been added as a flux.

Barium borate preparation

In an aluminum foil electrolytic capacitor, the anode foil bears both a layer of hydrous aluminum oxide and a layer of barrier dielectric oxide and is in contact with an electrolyte containing as additives up to 5 wt % depolarizer and sufficient soluble phosphate salt to restore the desired anodization voltage.

Aluminum electrolytic capacitor

An aluminum electrolytic capacitor has a capacitor section of two aluminum electrode foils, at least one of which bears a barrier layer anodic oxide, wound with interleaved spacer material in contact with an electrolyte containing a phosphate salt, the cation of which is compatible with the cation of the electrolyte solute to prevent precipitation of a phosphate.

An aluminum electrolytic capacitor capable of operation at 150 VDC or higher and 105.degree. C. contains as its electrolyte a diisopropylamine or a triethylamine mono salt of azelaic acid dissolved in a solvent mixture of ethylene glycol, ethylene glycol and N-methylpyrrolidinone, ethylene glycol N-methylpyrrolidinone and dimethylformamide, butyrolactone, or butyrolactone and N-methylpyrrolidinone, all containing small amounts of water.

Electrolytic capacitor for at least 150 V service

An aluminum electrolytic capacitor contains as electrolyte 79-95 wt. % of an azeotrope of acetic or propionic acid and triethylamine or tri-n-propylamine, 5-20 wt. % water, and up to 1 wt. % phosphoric acid.

Electrolytic capacitor

A high-temperature aluminum electrolytic capacitor contains an electrolyte of a salt of tert.butylamine and adipic acid in a 1.3 to 2.0 amine:acid molar ratio, a phosphate salt, and water dissolved in ethylene glycol to provide a capacitor capable of operating at least at 200 VDC and 130.degree. C.

High temperature electrolytic capacitor

An electrolytic capacitor contains an electrolyte solvent system in which one component is an acceptor in hydrogen bonding while the other component is one that can function both as acceptor and donor in hydrogen bonding. The solute or solutes present must not interact with either solvent component. When the above conditions are met, the result is an electrolyte whose resistivity curve passes through a minimum.

Electrolytic capacitor containing a mixed solvent system

An aluminum electrolytic capacitor suitable for low-voltage use contains as electrolyte ammonium difluoroacetate dissolved in either ethylene glycol or an ethylene glycol-butyrolactone mixture both containing water. The electrolyte has a room-temperature resistivity of 150 ohm-cm or less and a -40.degree. C. resistivity of less than 11,000 ohm-cm.

Low voltage electrolytic capacitor

Anomalous substituted-amine or quaternary ammonium salts of dibasic acids have two dibasic acid molecules per cation of three per two cations.

Anomalous salts of dibasic acids

An aluminum electrolytic capacitor capable of operation at 200 VDC or higher and 130.degree. C. contains as its electrolyte a tertiary amine or a dipropylamine mono salt of dodecanedioic acid dissolved in a solvent mixture of ethylene glycol and N-methyl-2-pyrrolidinone and water.

Electrolytic capacitor for at least 200 V service

A high-temperature aluminum electrolytic capacitor contains an electrolyte of mono(di-n-propylammonium) adipate or mono(diisopropylammonium) adipate, a phosphate salt, and water dissolved in ethylene glycol to provide a capacitor capable of operating at least at 200 VDC and 130.degree. C.

An electrolytic capacitor contains as electrolyte a metatungstate salt dissolved in a polar solvent. The salt is preferably an ammonium or amine salt, and the solvent consists essentially of at least one polar organic solvent and water.

Electrolytic capacitor containing a metatungstate electrolyte

An electrolytic capacitor contains an electrolyte of ammonium anthranilate dissolved in a polar organic solvent.

Capacitor containing anthranilate electrolyte

A non-aqueous electrolyte for an electrolytic capacitor contains as solute a salt obtained from an amine and a trialkyl phosphate.

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North Adams, MA, United States of America

Manuel Finkelstein