Hitachi Metals, Ltd.

Takashi Meguro

Hideki Nakamura

Yasunobu Ogata

Yoshio Bizen

Tsutomu Inui

Yoshizo Sawada

Yoichi Mochida

Yoshihito Yoshizawa

Shunsuke Arakawa

Setsuo Mishima

Noboru Hanai

Kaoru Masuda

Michihiro Nagao

The method for producing a mother alloy for an iron-based amorphous alloy has the steps of (a) melting raw materials for elements constituting the amorphous alloy together with at least one oxide of an element constituting the amorphous alloy, the raw materials containing aluminum as an inevitable impurity, and the oxide having a smaller standard free energy of formation than that of Al O in an absolute value; and (b) removing the resultant Al O from the melt, thereby reducing the content of aluminum to 50 ppm or less in the melt.

Method for producing mother alloys for iron-based amorphous alloys

A soft magnetic alloy strip is manufactured by a single roll method. The soft magnetic alloy strip is 0.2&times;d mm or less (, which &ldquo;d&rdquo; is a width of the strip,) in warpage in the widthwise direction of the strip, and has a continuous, long length not less than 50 m, in which a width of an air pockets occurring on a roll contact face is not more than 35 &mgr;m, a length of the air pockets is not more than 150 &mgr;m, and the centerline average roughness Ra of the roll contact face is not more than 0.5 &mgr;m.

Soft magnetic alloy strip, magnetic member using the same, and manufacturing method thereof

Disclosed are a target material for magneto-optical recording medium having a structure formed by sintering of an RE-TM phase (A) having a composition with an RE content higher than that of the composition of an intermetallic compound represented by the chemical formula TM.sub.2 RE, and a TM-RE phase (B) having a composition with an RE content equal to or lower than that of the composition of an intermetallic compound represented by the chemical formula TM.sub.2 E, wherein RE denotes at least one rare earth element selected from the group of elements consisting of Nd, Gd, Tb, Dy, Ho and Er, and TM denotes at least one element selected from the group of metals of the iron group which consists of Fe, Co and Ni; and a process for producing the same.

Target for magneto-optical recording medium and process for production

A flat-shaped fine Fe-Ni alloy powder suitable for use as a magnetic shield coating material for cards or the like. The powder has a mean particle size of 0.1 to 30 .mu.m, a mean thickness not greater than 2 .mu.m and a coercive force not greater than 400 A/m. The flat-shaped fine powder is produced by preparing an Fe-Ni alloy powder of a composition which exhibits, in a bulk state, a saturated magnetostriction constant value falling within the range of .+-.15.times.10.sup.-6 and which contains, by weight, 70 to 83% Ni, 2 to 6% Mo, 3 to 6% Cu, 1 to 2% Mn, not more than 0.05% C and the balance Fe and incidental impurities, pulverizing the alloy powder by an attrition mill, and annealing the pulverized powder in a fluidized or moving state in a substantially non-oxidizing atmosphere.

Fe-Ni alloy fine powder of flat shape

A flat-shaped fine Fe-Ni alloy powder suitable for use as a magnetic shield coating material for cards or the like. The power has a mean particle size of 0.1 to 30 .mu.m, a mean thickness not greater than 2 .mu.m and a coercive force not greater than 400 A/m. The flat-shaped fine powder is produced by preparing an Fe-Ni alloy powder of a composition which exhibits, in a bulk state, a saturated magnetostriction constant value falling within the range of .+-.15.times.10.sup.-6 and which contains, by weight, 70 to 83% Ni, 2 to 6% Mo, 3 to 6% Cu, 1 to 2% Mn, not more than 0.05% C and the balance Fe and incidental impurities, pulverizing the alloy powder by an attrition mill, and annealing the pulverized powder in a fluidized or moving state in a substantially non-oxidizing atmosphere.

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.

Method of heat-treating amorphous material

A method of producing high-grade metal or alloy powder, improved to eliminate undesirable inclusions and to reduce the production cost. A solid electrode material made of a metal or alloy, having a composition substantially equal to the composition of aimed metal or alloy powder, is heated and molten in a vacuum chamber by application of a plasma, arc, electron beam or laser beam. The molten metal or alloy in the form of droplets fall into collision with the surface of a roll rotating at a high speed so as to be pulverized and partially solidified. The particles of the metal or alloy scattered by the roll is directed to one side of the roll and are spheroidized and solidified into fine particles before they are collected in a collecting box disposed at one side of the roll within the vacuum chamber.

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Yonago, Japan

Takashi Meguro