Shin-etsu Chemical Co., Ltd.

Satoshi Shima

Noriaki Hamaya

Hajime Nakano

Naofumi Shinya

Takao Maeda

Masaki Kasashima

Masatoshi Ishii

Yukihiro Kuribayashi

Hiroto Sugahara

A Group IIIA element fluoride-containing coating comprising a Group IIIA element fluoride phase which contains at least 50% of a crystalline phase of the orthorhombic system belonging to space group Pnma is formed on a member for imparting corrosion resistance so that the member may be used in a corrosive halogen species-containing atmosphere. When the state of a crystalline phase is properly controlled, the coating experiences only a little color change by corrosion. A Group IIIA element fluoride-containing coating having a micro-Vickers hardness Hv of at least 100 is minimized in weight loss by-corrosion.

Fluoride-containing coating and coated member

An object of the present invention is to provide a hydrogen absorbing alloy which can improve a high rate discharge property while suppressing particle size reduction, exhibits cycle life characteristics equal to or higher than those of conventional alloys even when its cobalt content is decreased, and has a high capacity. Specifically, the present invention provides a hydrogen absorbing alloy having a CaCu type crystal structure in its principal phase, wherein the La content in the alloy is in the range of 24 to 33% by weight and the Mg or Ca content in the alloy is in the range of 0.1 to 1.0% by weight, as well as the aforesaid alloy wherein the Co content in the alloy is not greater than 9% by weight.

Hydrogen absorbing alloy and nickel-metal hydride rechargeable battery

The present invention provides a hydrogen absorbing alloy compact for use as the negative electrode of an alkaline rechargeable battery which is made without the aid of a current-collecting support, contains a binder dispersed in the interstices formed by mutual contact of hydrogen absorbing alloy particles and on the alloy surfaces, and has a bulk density of 3.5 to 6.0 g/cm . The present invention also provides a compact electrode which is made by forming a porous hydrogen absorbing alloy compact containing neither current-collecting support nor binder, impregnating the compact with an aqueous solution (or solvent solution) of a binder, and then drying the compact to remove the water (or solvent) alone, so that the strength of the compact is increased and good electrical contact between alloy particles is established.

Hydrogen absorbing alloy compact for use as the negative electrode of an alkaline rechargeable battery

An object of the present invention is to provide a hydrogen absorbing alloy powder for use in the negative electrodes of alkaline rechargeable batteries which has excellent initial characteristics and a high rate discharge property, exhibits satisfactory life characteristics, and is hence very beneficial from a practical point of view, as well as a process for producing the same. Specifically, the present invention provides a hydrogen absorbing alloy powder for use in the negative electrodes of alkaline rechargeable batteries which has an average particle diameter of 5 to 20 &mgr;m and an oxygen content of 2,000 to 6,000 ppm and, moreover, wherein the oxygen on the surfaces of hydrogen absorbing alloy particles is present in the form of hydroxyl groups.

Hydrogen absorbing alloy powder for use in the negative electrodes of alkaline rechargeable batteries and process for producing the same

Provided is a hydrogen absorbing alloy powder for use in nickel-metal hydride storage batteries having a high capacity, excellent initial characteristics and a long life. Specifically provided is a process for the production of a hydrogen absorbing alloy powder which includes the steps of treating a hydrogen absorbing alloy powder with an acid solution, and subsequently treating the hydrogen absorbing alloy powder with a solution containing a condensed phosphoric acid having 2 to 20 phosphorus atoms per molecule and/or phytic acid, as well as an electrode formed of the hydrogen absorbing alloy powder produced by the above process. Also provided is a hydrogen absorbing alloy powder of the AB,type in which A is exothermic metal and B is endothermic metal, the hydrogen absorbing alloy powder being obtained by providing a hydrogen absorbing alloy in which A comprises a mixture composed of 20 to 50% by weight of Ce, 20 to 50% by weight of La, and the balance comprising rare earth elements other than Ce and La and inclusive of Y (yttrium), treating the hydrogen absorbing alloy powder with an acid solution, and further treating the hydrogen absorbing alloy powder with a solution containing a phosphorus compound, as well as an electrode formed of this hydrogen absorbing alloy powder.

Hydrogen absorbing alloy powder and electrodes formed of the hydrogen absorbing alloy powder

The object is to provide a hydrogen absorbing alloy suitable for the negative electrode of a Ni-hydrogen storage battery which is effective at low temperatures. The object can be attained by a LaNi.sub.5 type hydrogen absorbing alloy, wherein the content of Mg in the hydrogen absorbing alloy is 50 to 500 ppm, and it is represented by a general formula RNi.sub.a Co.sub.b Al.sub.c M.sub.d, wherein R comprises not less than 77 wt % La and 23 wt % or less of one or more metals other than La, Ni, Co, Al and M, M comprises at least one kind of metals selected from the group consisting of Fe, Cr, Cu and Mn, and a to d denote a positive number within a predetermined range. In addition, it is important to contain a small amount of Ti, Pb, oxygen, carbon and/or sulfur in said alloy.

Hydrogen absorbing alloy for a negative electrode of an alkaline storage

Provided is a hydrogen absorbing alloy suitable for a negative electrode of an Ni--hydrogen storage battery effective at low temperature, more specifically, a R--Ni type of hydrogen absorbing alloy represented by a general formula RNi.sub.a Co.sub.b Al.sub.c M.sub.d, and with Mo content of 50 to 500 ppm wherein R expresses not less than 18 wt % Pr and one or more metals other than Pr, Ni, Co, Al and M, and M expresses one or more metals selected from the group consisting of Fe, Cr, Cu, and Mn, and a to d expresses positive numbers in the specified range Moreover, the above alloy further containing trace amounts of Mg, Ti, Pb, oxygen, carbon, and/or sulfur is provided.

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Fukui-ken, Japan

Satoshi Shima