摘要:
Disclosed is a magnetic recording medium comprised of a substrate and a layer of magnetic powder coated on a surface of the substrate, characterized in that the magnetic powder is hexagonal crystals having single domain crystalline magnetic anisotropy, particle sizes of 0.01 to 0.3 .mu.m, particle size/thickness ratios of 2.3 to 15 and the tapping packing rate of said magnetic powder is 15% or more.
摘要:
A hexagonal ferrite magnetic powder for high density magnetic recording, having an improved dispersibility in a binder or paint is obtained by melting a mixture of hexagonal ferrite-forming components and a glass-forming component, and rapidly cooling the resultant molten mixture to obtain an amorphous material. The amorphous material is thermally treated to precipitate fine particles of the hexagonal ferrite therein. The amorphous material containing the precipitated fine particles is dissolved such that the glass-forming component remains on each of said fine particles in an amount of 0.01 to 0.3% by weight based on the weight of the particles.
摘要:
A method for preparing a magnetic powder for high density magnetic recording includes melting a mixture containing the fundamental component of a hexagonal ferrite, a substituting component for reducing the coercive force, and a glass forming material. The resultant molten material is rapidly cooled to obtain an amorphous body which is then heat-treated to produce desired substituted type hexagonal ferrite particles in the glass matrix.
摘要:
Disclosed is a magnetic powder for high-density magnetic recording, formed of a substituted hexagonal ferrite possessing an average particle diameter in the range of 0.01 to 0.2 .mu.m and a coercivity in the range of 200 to 2,000 Oe and characterized by the fact that the substituted hexagonal ferrite has at least 0.05 to 0.5 atom of at least one element selected from the group consisting of Zr and Hf per chemical formula and at least one element selected from among the elements other than Zr and Hf substituted for part of the Fe atom of the ferrite, and a magnetic recording medium of the present invention comprises a substrate and the magnetic powder mentioned above deposited on the substrate. Since the magnetic powder comprises very minute particles, the magnetic powder and the magnetic recording medium are capable of high-density recording. The magnetic powder has an improved desirably controlled aspect ratio for orientation and the temperature characteristic of coercivity (Hc) as compared with the countertype formed of a hexagonal ferrite which has neither Zr nor Hf substituted for the Fe atom.
摘要:
A magnetic powder for magnetic recording media comprises a hexagonal crystalline system ferrite containing, as essential components for said hexagonal crystalline system ferrite, iron and oxygen, and at least one of the elements selected from the group of Ba, Sr, Ca and Pb, said iron being substituted by at least one of the elements selected from the group of Ti, Co, Ni, Mn, Cu, Zn, In, Ge, Nb, Zr and Sb; and at least one of Ba, Sr, Ca, Pb being substituted by at least one of the rare earth elements selected from the group of Ce, Pr, Nd, Pm, Sm and Eu. The magnetic powder has a mean particle size of 0.01 to 0.3 .mu.m and a coercive force of 200 and 2000 Oe. The magnetic powder is improved in its saturation magnetization while retaining a suitable coercive force. Accordingly, high reproduction output can be obtained in a magnetic recording medium employing the magnetic powder.
摘要:
A method for preparing a magnetic powder for high density magnetic recording includes melting a mixture containing the fundamental component of a hexagonal ferrite, a substituting component for reducing the coercive force, and boron trioxide as a glass forming substance in predetermined amounts. The resultant molten material is rapidly cooled to obtain an amorphous body which is then heat-treated to produce desired substituted type hexagonal ferrite particles in the glass matrix.
摘要:
In the magnetic recording medium according to the present invention comprising a magnetic recording medium layer where a magnetic paint containing Ba ferrite magnetic powder is coated on the substrate, Hc in the oriented direction ranging from 900 to 1500 Oe, the squareness in the oriented direction being 0.80 or more, and the ratio Hr(90.degree.)/Hr(0.degree.) of the remanence coercive force Hr(0.degree.) in the oriented direction (0.degree.) and the remanence coercive force Hr (90.degree.) in the direction (90.degree.) perpendicular to the oriented direction ranging from 1
摘要:
Disclosed is a barium ferrite magnetic powder comprising particles characterized by (A) a mean particle size of 0.3 .mu.m or smaller and (B) the presence of Sr, Ca and Si in respective amounts of 0.2 wt. % or less as SrO, 0.15 wt. % or less as CaO, and 0.3 wt. % or less as SiO.sub.2. Also disclosed is a recording medium comprising the barium ferrite magnetic powder.
摘要:
A matnetic recording powder comprising a hexagonal barium ferrite substituted with a coercive force control element. This magnetic powder is preliminarily treated with sulfate ion-containing water so as to convert any free barium ions in the magnetic powder to a water insoluble compound such as BaSO.sub.4 or BaS.sub.2 O.sub.7. There is also proposed a magnetic recording medium having a magnetic layer containing such a magnetic powder as mentioned above.
摘要翻译:一种包含被矫顽力控制元件取代的六方晶系钡铁氧体的生物记录粉末。 该磁性粉末用含硫酸根离子的水预先处理,以将磁性粉末中的任何游离的钡离子转化为不溶于水的化合物如BaSO 4或BaS 2 O 7。 还提出了具有如上所述的含有这种磁性粉末的磁性层的磁记录介质。
摘要:
A powder for a magnetic recording medium comprising a plurality of magnetic particles and a coating covering the surfaces of the magnetic particles. The coating is a residue resulting from the thermal decomposition of an organic material. The powder is manufactured by applying one or more organic materials to the surfaces of a plurality of magnetic particles by dispersing the magnetic particles in a solution containing the organic material. The magnetic particles, having the organic material as a coating, are separated from the solution, and the magnetic particles are heated to a temperature at which the organic material decomposes.