摘要:
A magnetic fluid comprising metal fine particles of cobalt, 25 to 60% based on the weight of the metal particles of a surface-active agent selected from the group consisting of polyglycerine fatty acid esters, sorbitan fatty acid esters, and mixtures thereof, and 50 to 250% based on the weight of the metal particles of a low boiling hydrocarbon medium exhibits remarkably high saturation magnetization.
摘要:
A magnetic fluid comprising metal fine particles of cobalt, a nonionic or oil-soluble anionic surface-active agent, and a low-volatile solvent exhibits remarkably high saturation magnetization.
摘要:
A magnetic fluid comprising metal fine particles of iron, 50 to 100 wt % of the metal particles of a surface-active agent selected from phospholipids, and 100 to 800 wt % of the metal particles of a medium in the form of a diester of an aliphatic dicarboxylic acid exhibits remarkably high saturation magnetization.
摘要:
By laminating soft magnetic sheets 1, 11, a laminated soft magnetic member 5 in which insulating layers and soft magnetic metal layers are alternately laminated is produced. In this case, prior to laminating the obtained soft magnetic sheets 1, 11, or posterior to obtaining the laminated soft magnetic member 5 by laminating the soft magnetic sheets 1, 11, heat treatment is conducted under the conditions predetermined depending on the purpose of the heat treatment. During the heat treatment, pressing treatment can also be conducted concurrently. Additionally, when the heat treatment is conducted under the condition in which a tension is applied, further improvement of the magnetic properties can be expected.
摘要:
The invention is a magnetic recording medium which is effectively protected against forgery by the alteration of recorded data, and a method for carrying out writing and reading on this magnetic recording medium. The magnetic recording medium of the invention comprises a recording material composed of a crystalline alloy containing Fe and Al . In the recoding material, the total amount of Fe and Al is at least 90 at % and the atomic ratio Al/(Fe+Al) ranges from 0.30 to 0.45. The recording material changes from a disordered phase to an ordered phase by heating. The recording material has a saturation magnetization of at least 45 emu/g prior to heating and lowers its saturation magnetization by at least 35 emu/g upon heating. Dark regions are observable in a bright-field image of the recording material by transmission electron microscopy, the dark regions accounting for 15-60% of the recording material in areal ratio and having a maximum breadth of 10-200 nm.
摘要:
An object of the present invention is to provide a method for producing an electromagnetic wave absorbing sheet with properties thereof further improved. A treated powder P0 pulverized and flaked in a pulverizing step is placed in a centrifugal gas-flow classifier 50. The treated powder is classified into a flaky soft magnetic metal powder P1 and a non-flaky powder P2 on the basis of the difference between the centrifugal force and the drag acting on each of these powders in a gas flow circling in a chamber 51. The non-flaky powder P2 is eliminated and the flaky soft magnetic metal powder P1 is used to form an electromagnetic wave absorbing sheet, the performances of the electromagnetic wave absorbing sheet being thereby improved. The classified non-flaky powder P2 is preferably recycled as the raw material powder used in the pulverizing step.
摘要:
A flat soft magnetic material to be used for a noise-suppressing magnetic sheet, wherein the 50% particle size D50 (μm), coercive force Hc (A/m) and bulk density BD (Mg/m3) of the flat soft magnetic material satisfy the following formula (1). D50/(HC×BD)≧1.5 (1)
摘要:
The performance index μ′×Q of a magnetic core member, in which an Fe—Si—Cr alloy is used, is further improved. A flaky soft magnetic metal powder, which is used in a magnetic core member for an RFID antenna comprising the above flaky soft magnetic metal powder and a binder, wherein it is composed of an Fe—Si—Cr alloy having an Ms (saturation magnetization)/Hc (coercive force) of 0.8 to 1.5 (mT/Am−1) in an applied magnetic field of 398 kA/m. In the present invention, it is preferable that the flaky soft magnetic metal powder consists of 7 to 23 at % of Si, 15 at % or less of Cr (excluding 0), and the balance being Fe and inevitable impurities, and that it has a weight-average particle size D50 of 5 to 30 μm and an average thickness of 0.1 to 1 μm.
摘要:
The object of the present invention is to provide an electromagnetic wave absorbing sheet excellent in permeability in high frequencies and to provide a method for manufacturing the same. The electromagnetic wave absorbing sheet of the present invention comprises insulating layers on the both sides of a magnetic layer. The magnetic layer is formed by densely depositing a large amount of magnetic powder such that the powder undergoes plastic deformation. Each magnetic powder is made to be a composite magnetic material formed of the soft magnetic metal phase consisting of a flaky soft magnetic metal powder and the insulating phase consisting of an insulating film formed on the surface of the soft magnetic metal phase. Additionally, another configuration can be taken in which a conductive layer is arranged on one of the insulating layers arranged on both sides of the magnetic layer, and the conductive layer is covered with an insulating layer.
摘要:
An iron system soft magnetic sintered body is prepared by blending an iron powder with a powder of a metal or ferroalloy so as to give a desired chemical composition and subjecting the blend to mechanical alloying, thereby alloying at least a portion of the metal or ferroalloy with iron, followed by shaping and firing. Alternatively, the same is prepared by treating an iron system alloy powder of a desired chemical composition by a mechanical grinding process, followed by shaping and firing. Even when starting with relatively large mean particle size powder, the resulting sintered body has a high density and improved magnetic properties.