Hitachi Maxell, Limited

Hitachi, Ltd.

Hitachi Maxwell, Ltd.

Kunio Wakai

Tetsuo Mizumura

Noboru Isoe

Takashi Kubota

Hideaki Niimi

Hideo Fujiwara

Akira Yano

Osamu Kitakami

Yoichi Ogawa

Hideo Kusada

Michio Asano

Minoru Ichijo

Fumio Kokai

Kazuetsu Yoshida

Hikaru Mizutani

Tsuyoshi Maro

Tsunemi Ohiwa

Susumu Shibasaki

Toshio Doi

Kiyotaka Ojima

Youichi Ogawa

A continuous plasma CVD apparatus, characterized in that frequency of high-frequency bias is in the range of 50-900 KHz, a blocking condenser is provided between a thin film and a high-frequency source so that the product C&middot;f of electrostatic capacity C of the blocking condenser and frequency f of the high-frequency source is 0.02 &lsqb;F&middot;Hz&rsqb; or more, and the total of impedances of all the rollers provided in the route of from a substrate unwind roller to a rotating drum is 10 k&OHgr; or more and the total of impedances of all the rollers provided in the route of from the rotating drum to a wind roller is 10 k&OHgr; or more. According to this apparatus, it becomes possible to continuously form a film without causing damage and deterioration of the substrate.

Plasma CVD apparatus

A continuous plasma CVD apparatus, characterized in that frequency of high-frequency bias is in the range of 50-900 KHz, a blocking condenser is provided between a thin film and a high-frequency source so that the product C.multidot.f of electrostatic capacity C of the blocking condenser and frequency f of the high-frequency source is 0.02 [F.multidot.Hz] or more, and the total of impedances of all the rollers provided in the route of from a substrate unwind roller to a rotating drum is 10 k.OMEGA. or more and the total of impedances of all the rollers provided in the route of from the rotating drum to a wind roller is 10 k.OMEGA. or more. According to this apparatus, it becomes possible to continuously form a film without causing damage and deterioration of the substrate.

A medium in which a magnetic layer is composed mainly of Co and oxygen and has a principal axis of magnetic anisotropy rising unidirectionally at 20.degree. to 80.degree. to a nonmagnetic substrate surface, the coercive force Hs on the surface side of the magnetic layer is 600 to 2,000 Oe and the coercive force Hb on the substrate interfacial side is less than 600 Oe, the medium being produced by treating a nonmagnetic substrate surface with a plasma in an atmosphere of an inert gas or an oxygen gas, and then depositing an alloy composed mainly of Co on the above plasma-treated nonmagnetic substrate surface while an oxygen gas is introduced into the layer-forming atmosphere.

Magnetic recording medium

A magnetic recording medium comprising a substrate and a ferromagnetic metal layer, wherein the ferromagnetic metal layer includes hydrated amorphous cobalt oxide, a X-ray photoelectron spectra which is characterized in that, in the Co.sub.2p spectrum, a ratio of a peak height at 785.9.+-.0.3 eV to that at 780.0.+-.0.3 eV is 40/100 or less when a background (BG) line is drawn between lower energy side leading edge points of peaks at 780.0.+-.0.3 eV (2p.sub.3/2) and 795.6.+-.0.3 eV (2p.sub.1/2) and, in the O.sub.1s spectrum, a ratio of a peak height at 529.3.+-.0.4 eV to that at 530.8.+-.0.4 eV is from 100:110 to 100:50 when a background line is drawn between the lower energy side leading edge point and the higher energy side leading edge point of a complex peak at 530.5.+-.2.5 eV from which the peaks at 529.3.+-.0.4 eV and 530.8.+-.0.4 are derived by peak synthesis, which has good corrosion and wear resistance.

Magnetic recording medium and method for producing the same

A perpendicular magnetic recording medium comprising a non-magnetic substrate and a magnetic layer which is formed on at least one surface of the substrate and comprises acicular particles of ferromagnetic metal oriented perpendicularly to a plane of the layer and an organic polymer filled in spaces between the acicular particles so as to surround the acicular particules, wherein a volume content of the organic polymer is about 5 to 55% by volume of the whole volume of the magnetic layer, which medium has not only good recording and reproducing characteristics but also improved durability.

Perpendicular magnetic recording medium and method for producing the same

The present invention provides a novel soft magnetic material superior in corrosion resistance which contains (a) a ferromagnetic metal and (b) a carbide of a ferromagnetic metal and/or a silicide of a ferromagnetic metal with at least one of (c) an amorphous carbon and/or an amorphous silicon and (d) a hydrocarbon polymer and/or a silicone polymer and which contains carbon atoms in an amount of 15 atomic % or less, preferably 9-15 atomic %, preferably prepared by the simultaneous vapor deposition of a ferromagnetic metal and a polymer.

Soft magnetic materials comprising 9 to 15 atomic percent carbon atoms

A magnetic recording medium comprising a substrate and, as a recording layer, a ferromagnetic metal thin layer formed on the substrate by deposition, in which the ferromagnetic metal thin layer contains oxygen atom in such a manner that concentrations of oxygen atom in a surface layer and an interfacial layer adjacent to the substrate are higher than that in an intermediate layer between the surface and interfacial layers, which has an improved coercive force and smaller magnetic domain.

Method of making a magnetic recording medium

The invention provides a magnetic recording medium having a ferromagnetic metallic layer provided on a non-magnetic substrate, and an anticorrosive deposited on said ferromagnetic metallic layer containing a benzotriazole derivative as a main component. A magnetic recording medium is also provided having on a substrate, a ferromagnetic metallic layer containing cobalt as a main component, a passivated cobalt layer on said ferromagnetic metallic layer and an anticorrosive layer on said passivated cobalt layer, said anticorrosive layer comprising at least one anticorrosive selected from benzothiazole derivatives, benzoimidazole derivatives haaving at least one of amino group, nitro group, chlorine and mercapto group as substituent in the benzoimidazole skeleton, benzotriazole, compounds containing nitrosonaphthol as a main component, oxime compounds, phytic acid and its derivatives, quinaldinic acid and its derivatives, quinoline compounds, naphthaldehyde and its derivatives. A process for producing the same is also provided.

Magnetic recording medium and process for producing the same

In a recording tape cartridge having a cartridge case, magnetic recording tape and a front lid and a rear lid for protecting the magnetic tape, there are provided entrance preventing members at a bottom the cartridge case facing to clearances between side edges of the front lid and case body for preventing entrance of harmful floating particles into the area near the recording tape so as to prevent corrosion of the recording tape.

Arrangement for preventing entrance of harmful particles for use in a

A magnetic recording medium comprising a substrate and, as a recording layer, a ferromagnetic metal thin layer formed on the substrate by deposition, in which the ferromagnetic metal thin layer contains oxygen atom in such a manner that concentrations of oxygen atom in a surface layer and an interfacial layer adjacent to the substrate are higher than that in an intermediate layer between the surface and interfacial layers, which has improved coercive force and smaller magnetic domain.

Magnetic recording medium and production thereof

A method of and an apparatus for making a magnetic recording tape, which is free from wrinkles formed thereon, by the use of a vapor deposition technique. A length of tape reeled on a supply reel is taken up by a take-up reel after having passed through a deposition station where it is movably turned around a cylindrical drum. In one aspect, the difference in tension between two different portions of the tape moving between the drum and the take-up reel and on respective sides of a tensioning roll forming a part of at least one tension control mechanism is adjusted to a value not greater than 10N/mm.sup.2. In another aspect, a charge eraser is employed and installed in the vicinity of the drum for removing an electrostatic charge built up in the tape being moved from the drum onto the take-up reel. In a further aspect, the cylindrical drum is used having its outer peripheral surface roughened to a ten-point average surface roughness of not smaller than 0.1 .mu.m.

Method of a making magnetic recording medium

A magnetic recording medium comprising a substrate, a magnetic layer provided thereon, a passivated film formed on the surface of said magnetic layer, and a lubricant-containing back-coat layer whose pH is adjusted to 6.3 or more on the back of said substrate.

A magnetic recording medium which comprises a substrate, a magnetic layer on the substrate and a protective layer which is formed directly on the magnetic layer or on an undercoat layer formed on the magnetic layer, the protective layer comprising a carbonaceous material essentially consisting of carbon, hydrogen and oxygen, which has improved traveling properties and abrasion resistance.

Magnetic recording medium and production of the same

A magnetic recording medium comprising a substrate, a magnetic layer and a protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atoms increasing towards the outer surface of the protective layer, which has improved durability and corrosion resistance.

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Ibaraki, Japan

Kunio Wakai