Hitachi Metals, Ltd.

Hitachi, Ltd.

Neomax Co., Ltd.

Jidosha Kiki Co., Ltd.

Hitachi Research Dev. Corp.

Yasunobu Ogata

Takashi Takami

Yutaka Kubota

Yoshizo Sawada

Mitsuhiro Kudo

Shinji Takayama

Takashi Meguro

Shuichi Shiina

Yoshinori Kobayashi

Kazuo Shiiki

Shigekazu Otomo

Katsunori Iwasaki

Mitusuke Masaka

Tsutomu Iimura

Etsushi Oda

Seiichi Hosokawa

Yusuke Iyori

Masahiro Tobise

Yasuo Tsukuda

Kenzi Maruta

Mikio Yamamoto

Mikio Shindo

Hiroshi Okajima

Koichiro Kurihara

Toshiyuki Kasakoshi

Kouji Hatanaka

An oxide magnetic material includes a ferrite with a hexagonal structure as its main phase. Metallic elements included in the oxide magnetic material are represented by the formula:CaLaSrFeCo,where atomic ratios x, x' and y and a molar ratio n satisfy 0.4&#x2266;x&#x2266;0.6, 0.01&#x2266;x&#x2032;&#x2266;0.3, 0.2&#x2266;y&#x2266;0.45 and 5.2&#x2266;n&#x2266;5.8, respectively.

Oxide magnetic material

A sintered ferrite magnet having a basic composition represented by the general formula: ACaRFeCoO(atomic ratio), wherein a, b, c and d represent the amounts of an A element, Ca, an R element and Co added in the pulverization step of an oxide magnet material, which are numerals meeting the conditions of 0.03&#x2266;x&#x2266;0.4, 0.1&#x2266;y&#x2266;0.6, 0&#x2266;z&#x2266;0.4, 4&#x2266;n&#x2266;10, x+y&#x3c;1, 0.03&#x2266;x+b&#x2266;0.4, 0.1&#x2266;y+c&#x2266;0.6, 0.1&#x2266;z+d&#x2266;0.4, 0.50&#x2266;[(1&#x2212;x&#x2212;y+a)/(1&#x2212;y+a+b)]&#x2266;0.97, 1.1&#x2266;(y+c)/(z+d)&#x2266;1.8, 1.0&#x2266;(y+c)/x&#x2266;20, and 0.1&#x2266;x/(z+d)&#x2266;1.2.

Ferrite sintered magnet

A ferrite magnet having a basic composition represented by the following general formula: (AR)O.n[(FeM)O] by atomic ratio, wherein A is Sr and/or Ba, R is at least one of rare earth elements including Y, M is at least one element selected from the group consisting of Co, Mn, Ni and Zn, and x, y and n are numbers meeting the conditions of 0.01&#x2266;x&#x2266;0.4, [x/(2.6n)]&#x2266;y&#x2266;[x/(1.6n)], and 5&#x2266;n&#x2266;6, and substantially having a magnetoplumbite-type crystal structure, is obtained by uniformly mixing a compound of Sr and/or Ba with an iron compound; calcining the resultant uniform mixture; adding a compound of the R element and/or the M element to the resultant calcined powder at a pulverization step thereof; and sintering the resultant mixture. The compound of the R element and/or the M element may be added at a percentage of more than 0 atomic % and 80 atomic % or less, on an element basis, at a mixing step before calcination.

Anisotropic, sintered ferrite magnet and method for producing the same

A ferrite magnet having a basic composition represented by the following general formula: (AR)O.n[(FeM)O] by atomic ratio, wherein A is Sr and/or Ba, R is at least one of rare earth elements including Y, M is at least one element selected from the group consisting of Co, Mn, Ni and Zn, and x, y and n are numbers meeting the conditions of 0.01&#x2266;x&#x2266;0.4, [x/(2.6n)]&#x2266;y&#x2266;[x/(1.6n)], and 5&#x2266;n&#x2266;6, and substantially having a magnetoplumbite crystal structure, is obtained by uniformly mixing a compound of Sr and/or Ba with an iron compound; calcining the resultant uniform mixture; adding a compound of the R element and/or the M element to the resultant calcined powder at a pulverization step thereof; and sintering the resultant mixture. The compound of the R element and/or the M element may be added at a percentage of more than 0 atomic % and 80 atomic % or less, on an element basis, at a mixing step before calcination.

Ferrite magnet and both rotor and magnet roll comprising the same

A ferrite magnet having a basic composition represented by the following general formula: (A R )O.n&lsqb;(Fe M ) O &rsqb; by atomic ratio, wherein A is Sr and/or Ba, R is at least one of rare earth elements including Y, M is at least one element selected from the group consisting of Co, Mn, Ni and Zn, and x, y and n are numbers meeting the conditions of 0.01&lE;x&lE;0.4, &lsqb;x/(2.6n)&rsqb;&lE;y&lE;&lsqb;x/(1.6n)&rsqb;, and 5&lE;n&lE;6, and substantially having a magnetoplumbite crystal structure, is obtained by uniformly mixing a compound of Sr and/or Ba with an iron compound; calcining the resultant uniform mixture; adding a compound of the R element and/or the M element to the resultant calcined powder at a pulverization step thereof; and sintering the resultant mixture. The compound of the R element and/or the M element may be added at a percentage of more than 0 atomic % and 80 atomic % or less, on an element basis, at a mixing step before calcination.

Method for producing ferrite magnet

A resin-bonded magnet composed substantially of (a) an R&mdash;T&mdash;N-based magnetic powder having a basic composition of R T N , wherein R is at least one selected form the group consisting of rare earth elements including Y, T is Fe or Fe and Co, 5&lE;&agr;&lE;20, and 5&lE;&bgr;&lE;30, (b) a ferrite magnetic powder having a substantially magnetoplumbite-type crystal structure and a basic composition represented by (A R&prime; ) O&lsqb;(Fe M ) O &rsqb; by atomic ratio, wherein A is Sr and/or Ba, R&prime; is at least one selected from the group consisting of rare earth elements including Y, La being indispensable, M is Co or Co and Zn, 0.01&lE;x<0.4, 0.005&lE;y&lE;0.04, and 5.0&lE;n&lE;6.4, and (c) a binder. The ferrite magnet powder is preferably an anisotropic, granulated powder or an anisotropic, sintered ferrite magnet powder.

Resin-bonded magnet, its product, and ferrite magnet powder and compound used therefor

A ferrite powder for bonded magnets having a substantially magnetoplumbite-type crystal structure and an average diameter of 0.9-2 &mgr;m, the ferrite powder having a basic composition represented by the following general formula: (A R )O.n&lsqb;(Fe M ) O &rsqb; by atomic ratio, wherein A is Sr and/or Ba; R is at least one of rare earth elements including Y, La being indispensable; M is at least one element selected from the group consisting of Co, Mn, Ni and Zn; and x, y and n are numbers meeting the conditions of 0.01&lE;x&lE;0.4, &lsqb;x/(2.6n)&rsqb;&lE;y&lE;&lsqb;x/(1.6n)&rsqb;, and 5&lE;n&lE;6, (Si&plus;Ca) being 0.2 weight % or less, and (Al&plus;Cr) being 0.13 weight % or less, can be produced by mixing iron oxide containing 0.06 weight % or less of (Si&plus;Ca) and 0.1 weight % or less of (Al&plus;Cr) with compounds of A, R and M elements, calcining the resultant mixture for ferritization, pulverizing the resultant magnetically isotropic ferrite and then heat-treating the pulverized ferrite at 750-950&deg; C. for 0.5-3 hours in the air.

Bonded magnet, magnet roll, a ferrite powder used therefor and method for producing same

A ferrite powder for bonded magnets having a substantially magnetoplumbite-type crystal structure and an average diameter of 0.9-2 &mgr;m, the ferrite powder having a basic composition represented by the following general formula: (A,R,O.n&lsqb;Fe,M,),O,&rsqb; by atomic ratio, wherein A is Sr and/or Ba; R is at least one of rare earth elements including Y, La being indispensable; M is at least one element selected from the group consisting of Co, Mn, Ni and Zn; and x, y and n are numbers meeting the conditions of 0.01&lE;x&lE;0.4, &lsqb;x/(2.6n)&rsqb;&lE;y&lE;&lsqb;x/(1.6n)&rsqb;, and 5&lE;n&lE;6, (Si&plus;Ca) being 0.2 weight % or less, and (Al&plus;Cr) being 0.13 weight % or less, can be produced by mixing iron oxide containing 0.06 weight % or less of (Si&plus;Ca) and 0.1 weight % or less of (Al&plus;Cr) with compounds of A, R and M elements, calcining the resultant mixture for ferritization, pulverizing the resultant magnetically isotropic ferrite and then heat-treating the pulverized ferrite at 750-950&deg; C. for 0.5-3 hours in the air.

The ferrite magnet having a composition represented by the general formula: (A.sub.1-x R.sub.x)O.multidot.n�(Fe.sub.1-y M.sub.y).sub.2 O.sub.3 ! (by atomic ratio), wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, and x, y and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.y.ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively is produced by preparing a starting material powder having the above composition and an average particle size of 0.4-0.7 .mu.m, and subjecting the starting material powder to molding in a magnetic field and then to sintering.

Ferrite magnet and method for producing same

A method of producing a ferrite magnet which comprises the steps of wet-grinding ferrite powder contained in a slurry to prepare a slurry of fine ferrite particles; concentrating the slurry of fine ferrite particles to have a predetermined solid content; kneading the concentrated slurry to disperse the fine ferrite particles; wet-compacting the kneaded slurry to form a green body; and sintering the green body to obtain the ferrite magnet. The ferrite powder having the following composition:

Method of producing ferrite magnet

This invention provides a method for producing an oxide superconductor which has a uniform texture and is markedly high in sintered density and current density. The method involves the formation of intermediate products from the starting materials. The intermediate products are then used to form the final product. Specifically, to form an oxide superconducting material having a compositional formula

Method for producing ceramic superconducting material using intermediate

A glow plug for diesel engines in which a ceramic heater is supported, with the one end thereof cantilevered toward the outside, by the tip of a hollow holder; the ceramic heater is composed of a U-shaped heating portion and a pair of leads extending backwards from both ends of the U-shaped heating portion, both being formed integrally by an electrically conductive sintered sialon, which is formed by adding a small amount of Al.sub.2 O.sub.3 to a raw meal containing Si.sub.3 N.sub.4 as a principal ingredient, a small amount of AlN polytype and no greater than 5 wt. % of Y.sub.2 O.sub.3, and mixing the addition product with 23-70 vol. % of at least one type of Ti carbide, nitride and carbide-nitride; an insulating layer is provided on the outer periphery of at least one of the leads and bonded to, and held by, the inside of the holder; and the rear end of the other of the leads is connected by means of a metallic lead wire to an external connection terminal held in an insulated state at the lead end of said holder.

Glow plug for diesel engines

Amorphous alloys having high strength, high hardness, high crystallization temperature, high saturation magnetic induction, low coercive force, high magnetic permeability and particularly low deterioration of magnetic properties with lapse of time, have a composition formula of

Amorphous alloys

An alloy material for magnetic head which ensures, when formed into a head, reduced distortion during writing and reduced level of noises such as sliding noise, while presenting high wear resistance. The alloy material is produced by preparing a molten alloy having a basic composition consisting essentially of Fe and 4 to 8 wt % of Si, and further containing one or more than two additive element or elements selected from a group consisting of elements belonging in periodic table to groups IIA, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IVA and VA. The molten alloy is then quenched at a high cooling rate of at least 10.sup.3 .degree.C./sec to become a thin sheet having a thickness ranging between 0.02 mm and 0.3 mm. The sheet is then heat-treated in a non-oxidizing atmosphere at 600.degree. to 1200.degree. C. for 0.01 to 20 hours, so that the mean grain size of 0.2 mm or smaller can be obtained.

Magnetic head alloy material and method of producing the same

A method of heat-treating an amorphous material as that the amorphous material has a high magnetic permeability, is disclosed in which an amorphous material having a Curie temperature T.sub.c higher than or equal to its crystallization temperature T.sub.x is held for a short time at a temperature T satisfying relations T.gtoreq.0.95 T.sub.c and T.gtoreq.T.sub.x.

Growing community of inventors

Saitama-ken, Japan

Yasunobu Ogata