Fuji Photo Film Company, Limited

Akio Yanai

Ryuji Shirahata

Tadashi Yasunaga

Tatsuji Kitamoto

Koji Sasazawa

Yasuo Nishikawa

Yasuyuki Yamada

Makoto Nagao

Kyoichi Naruo

Masao Yabe

Nobuyuki Yamamoto

A magnetic recording medium having improved running properties and electromagnetic characteristics is disclosed, which comprises a non-magnetic support having provided thereon an underlayer and a magnetic layer composed of a thin ferromagnetic metal film in that order, said underlayer being composed mainly of a high molecular weight compound having on the surface thereof an uneven orange peel texture, wherein said underlayer has an average surface area of a unit cell of the uneven orange peel texture of from 3.times.10.sup.-6 to 3.times.10.sup.-3 mm.sup.2, and has a surface roughness of from 0.1 to 0.01 .mu.m.

Magnetic recording medium

The running properties and durability under a wide range of temperature and humidity conditions are improved by the presence of terminally modified polyhexafluoropropylene on a thin ferromagnetic metal film.

Magnetic recording media

A method and apparatus for producing a magnetic recording medium having an improved durability with a simple process. Nitrogen molecules and/or nitrogen atoms in an excited state are applied to a nonmagnetic substrate simultaneously with an iron vapor flow and an ion flow. The resulting magnetic recording medium has superior corrosion resistance and can be produced at a high film forming rate, and is especially suitable for high density recording because of its high coercive force.

Method for producing magnetic recording medium

A durable, rust- and scratch-resistant magnetic recording medium coated thereon a thin ferromagnetic film comprising an iron oxide nitride, wherein said film is an aggregation of pillar particles of said iron oxide nitride, said particles having a higher nitrogen content on their surface than inside the particles.

A method for producing a thin-film magnetic recording medium having an improved corrosion resistance and which permits production of the medium at a high speed. A magnetic material vapor flow from an evaporation source and a gas or ion flow are applied to a nonmagnetic base in an evaporation chamber and the two flows reacted with each other to form the thin-film magnetic layer on the nonmagnetic base. During this process, the expression P.sub.1 /P.sub.0 .ltoreq.0.1 is maintained, wherein P.sub.0 represents the degree of vacuum in the evaporation chamber, under a first condition where only the gas or ion flow is applied after the pressure in the chamber has been reduced to a predetermined degree of vacuum, and P.sub.1 represents the degree of vacuum in the chamber under a second condition where the magnetic material vapor flow is applied to the nonmagnetic base simultaneously with the gas or ion flow. The rate of formation of the thin-film magnetic layer is 200 .ANG./sec or more on the average.

Method for producing thin-film magnetic recording medium

A durable, weather-resistant and anti-corrosive magnetic recording medium is disclosed, which comprises a non-magnetic support having coated thereon a thin film type magnetic layer comprising iron, nitrogen oxygen and at least one element selected from the group consisting of titanium, silicon, aluminum and tantalum.

A magnetic recording medium, such as a tape, having a thin ferromagnetic film containing Fe.sub.a Co.sub.b N.sub.c O.sub.d satisfying: 32%.ltoreq.a.ltoreq.90%; 5%.ltoreq.b.ltoreq.55%; 2%.ltoreq.c.ltoreq.28%; 5%.ltoreq.d.ltoreq.23%; and c+d.ltoreq.40%. Such a film provides enhanced resistance against corrosion.

Magnetic recording medium containing Fe, Co, N and O

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a thin ferromagnetic metal film, wherein the thin ferromagnetic metal film contains an iron atom, a nitrogen atom and an oxygen atom within the following atomic percent ranges:

A method of preparing a ferromagnetic recording medium is disclosed. The method includes charging a ferromagnetic material in an evaporator. The material is then irradiated with an electron beam having a beam current density of at least 0.1 A/cm.sup.2 in order to evaporate the material. The evaporated material is vapor deposited on a continuously travelling support in order to from the recording medium. The vapor deposition type magnetic recording medium produced has good metal film adhesion and durability.

Method for preparing magnetic recording medium

A process for fabricating magnetic tape in which a tape substrate in passed through a stream of evaporating material so as to present a continuously varying angle of incidence to the stream. The maximum and minimum angles of incidence are defined. Oxidizing gas is applied to the tape at the minimum angle of incidence and at an intermediate angle.

Process for producing magnetic recording material

A magnetic recording medium comprising a magnetic recording layer formed on a non-magnetic substrate by depositing a ferromagnetic metal or alloy on the substrate, the recording layer containing oxygen atoms in such a manner that the ratio thereof gradually reduces from the substrate side to the surface of the recording layer except the portion thereof very near to the surface thereof. The recording layer may comprise many deposited magnetic films, each containing oxygen atoms distributed as described above or uniformly in a ratio different from those in the other magnetic films. In the latter case, a magnetic film positioned nearer to the substrate contains a higher ratio of oxygen atoms.

A process for producing a magnetic recording medium comprising heating a magnetic material evaporation source with at least one scanning electron beam and depositing a vapor of a magnetic material emitted from the magnetic material evaporation source onto a non-magnetic substrate tape or web which is continuously moving in a vacuum atmosphere, the magnetic material evaporation source being disposed substantially parallel to the width direction of the non-magnetic substrate tape or web to form a magnetic thin film thereon, wherein the scanning frequency of the electron beams is about 2wv/n Hz or more, in which v m/min is the moving speed of the non-magnetic substrate; w m is the scanning width of the electron beams on said magnetic material evaporation source; and n is the number of the electron beams. The magnetic thin film magnetic recording medium has improved (dB/dH).sub.max and an excellent envelope of reproduced signals.

Process for producing magnetic recording medium

A magnetic recording medium having a thin ferromagnetic metal film formed on a non-magnetic base by vacuum vapor deposition or ion plating is disclosed. The thin ferromagnetic metal film is based on Co and contains 0.05 to 3.0 wt % of Mg.

A process for producing a magnetic recording material comprising a support having a thin metal film layer provided thereon is described, the process comprising the steps of (1) coating a thin magnetic metal film having a water contact angle of at least 25.degree. with a polymer solution to form a thin polymer layer, drying the thin polymer layer, and providing a lubricant on the thin polymer layer, or (2) coating the thin magnetic metal film with a lubricant-containing polymer solution to form a lubricant-containing polymer layer, and drying the lubricant-containing polymer layer.

Process for producing magnetic recording materials

A system of manufacturing a magnetic recording medium in which a magnetic metal or alloy is heated and evaporated by an electron beam gun so that vacuum-evaporated magnetic film is formed on a non-organic or organic macromolecular base. A plasma generating coil is disposed near an evaporating source and an electron beam passes through the hollow portion of the coil in preferably a direction coaxial with the axis of the coil. High frequency power is applied to the coil and vacuum deposition is carried out with a plasma generated thereby. The flow of vapor of magnetic metal or alloy is applied obliquely to the base and an oxidation gas is introduced into a vacuum container for forming the magnetic film.

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Kanagawa, Japan

Akio Yanai