A punching method includes: punching out a plurality of electrical steel sheets in a stacked state by a mold, wherein sheet thicknesses of the electrical steel sheets are set to be 0.35 mm or less, a Vickers hardness (test force 1 kg) of the sheets is set to be 150 to 400, and an average crystal grain size of the sheets is set to be 50 to 250 μm, a clearance of the mold is set to be 7% or more of a minimum sheet thickness of the sheet thicknesses of the electrical steel sheets and equal to or lower than 7% of a total sheet thickness of the electrical steel sheets, and a pressure that a sheet presser of the mold applies to the electrical steel sheets is set to be 0.10 MPa or more.

An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5° C. or more and 25° C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.

A series of solid solutions AlFe.sub.2.sub._.sub.xMnxB.sub.2 have been synthesized by arc-melting and characterized by powder X-ray diffraction, and magnetic measurements. All the compounds adopt the parent AlFe.sub.2B.sub.2-type structure, in which infinite zigzag chains of B atoms are connected by Fe atoms into [Fe.sub.2B.sub.2] slabs that alternate with layers of Al atoms along the b axis. The parent AlFe.sub.2B.sub.2 is a ferromagnet with T.sub.c=282 K. A systematic investigation of solid solutions AlFe.sub.2.sub._.sub.xMn.sub.x.B.sub.2 showed a non-linear change in the structural and magnetic behavior. The ferromagnetic ordering temperature is gradually decreased as the Mn content (x) increases. The substitution of Mn for Fe offers a convenient method for the adjustment of the ferromagnetic ordering temperature of AlFe.sub.2B.sub.2.

A series of solid solutions AlFe.sub.2.sub._.sub.xMnxB.sub.2 have been synthesized by arc-melting and characterized by powder X-ray diffraction, and magnetic measurements. All the compounds adopt the parent AlFe.sub.2B.sub.2-type structure, in which infinite zigzag chains of B atoms are connected by Fe atoms into [Fe.sub.2B.sub.2] slabs that alternate with layers of Al atoms along the b axis. The parent AlFe.sub.2B.sub.2 is a ferromagnet with T.sub.c=282 K. A systematic investigation of solid solutions AlFe.sub.2.sub._.sub.xMn.sub.x.B.sub.2 showed a non-linear change in the structural and magnetic behavior. The ferromagnetic ordering temperature is gradually decreased as the Mn content (x) increases. The substitution of Mn for Fe offers a convenient method for the adjustment of the ferromagnetic ordering temperature of AlFe.sub.2B.sub.2.

Zinc is added to a metal magnetic alloy powder including iron and silicon. An element is formed using this magnetic material, and a coil is formed inside or on the surface of the element.

The present invention relates to a soft magnetic alloy containing: Ni, and at least one element selected from the group consisting of Al, Si and V, with the balance being Fe and inevitable impurities, in which, when the content of Ni and the total content of Al, Si and V are expressed by [Ni] and [M], respectively in mass %, and a relationship between [Ni] and [M] is plotted, the coordinate ([Ni], [M]) is present in a region surrounded by the straight lines A, B, C, D, and E.

An object of the present invention is to provide magnesium oxide for an annealing separator which is useful for obtaining grain-oriented electromagnetic steel sheets with excellent magnetic properties and insulating properties. To resolve the above object, an aspect of the present invention resides in magnesium oxide for an annealing separator which has a BET specific surface area of 12.0×10.sup.3 to 25.0×10.sup.3 m.sup.2.Math.kg.sup.−1 and a Blaine specific surface area of 2.0×10.sup.3 to 7.0×10.sup.3 m.sup.2.Math.kg.sup.−1.

An object of the present invention is to provide magnesium oxide for an annealing separator which is useful for obtaining grain-oriented electromagnetic steel sheets with excellent magnetic properties and insulating properties. To resolve the above object, an aspect of the present invention resides in magnesium oxide for an annealing separator which has a BET specific surface area of 12.0×10.sup.3 to 25.0×10.sup.3 m.sup.2.Math.kg.sup.−1 and a Blaine specific surface area of 2.0×10.sup.3 to 7.0×10.sup.3 m.sup.2.Math.kg.sup.−1.

Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.

Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.