Matsushita Electric Industrial Co., Ltd.

Mikio Murai

Masaru Odagiri

Kiyoshi Takahashi

Hideyuki Ueda

Kenji Kuwahara

Hiroshi Seki

Takashi Suzuki

Yukikazu Ohchi

Kiyosi Takahasi

Sadayuki Okazaki

Kunio Hibino

Yoshiaki Kai

Koichi Shinohara

Toshiaki Kunieda

Tatsuya Hiwatashi

Shigeki Kawase

Noriyasu Echigo

Norimoto Nouchi

Takashi Fujita

Hidetoshi Matsumoto

Takatoshi Minoda

Tetuo Fuchi

A lubricant composition having excellent lubricity and comprising at least one compound selected among fluorine compounds each having a perfluoroalkyl or perfluoroether group and an alkyl or alkenyl group in the molecule and at least one compound selected among fluorine compounds each having a perfluoropolyether group in the molecule; and a magnetic recording medium excellent in running durability and still durability and comprising a nonmagnetic substrate (1) and, formed thereon in this order, a ferromagnetic thin metal film (2), a carbon film (3), and a lubricant layer (4), wherein the lubricant layer (4) contains the lubricant composition.

Lubricant composition magnetic recording medium, and process for producing magnetic recording medium

A ferromagnetic metal thin film recording medium having a nonmagnetic substrate, a ferromagnetic metal thin film formed on the nonmagnetic substrate, a dry etched layer which is formed in a surface layer of the ferromagnetic metal thin film and contains oxygen atoms in a higher concentration than the remaining part of the ferromagnetic metal thin film, a hard carbonaceous film formed on the dry etched layer of the ferromagnetic metal thin film, a lubricant layer formed on said hard carbonaceous film, and optionally a modified layer which is formed on the hard carbonaceous film and has a thickness of less than 3 nm, and comprises carbon, nitrogen and oxygen atoms with an atomic ratio of nitrogen to carbon being at least 0.8%, which recording medium has improved running stability, durability and weatherability while maintaining electromagnetic conversion characteristics.

Method for producing a magnetic recording medium having a carbon

A magnetic recording medium of the present invention includes: a non-magnetic substrate; a ferromagnetic thin metal layer formed on the non-magnetic substrate; and a carbon layer and a lubricant layer in contact with the carbon layer, which is formed above the ferromagnetic thin metal layer so that the lubricant layer is an outermost layer, wherein the carbon layer contains nitrogen atoms, a Raman spectrum of the carbon layer has a peak A in the range of about 1310 to about 1410 cm.sup.-1 and a peak B in the range of about 1520 to about 1570 cm.sup.-1, and a ratio of integrated intensities of the peak A to the peak B is in the range of about 1.2 to about 2.0.

Magnetic recording medium having a carbon protective film containing

A magnetic recording medium produced by treating a magnetic recording medium which comprises a non-magnetic substrate and a magnetic layer formed on said substrate in an atmosphere kept at a temperature of at least 50.degree. C., with applying a tension of 1 gf. or less per 10 mm width to said magnetic recording medium in a treating time which is in a range on or above a line having a slope of at least 5000 in terms of .DELTA.ln(L)/.DELTA.(1/T) and passing a point of 0.5 second at 100.degree. C., when ln(L) is Arrhenius plotted against an inverse of an absolute temperature T (1/T), which medium has suppressed change of magnetic properties with time and improved corrosion resistance.

Method for producing magnetic recording medium

A magnetic recording medium comprising a non-magnetic substrate, a ferromagnetic thin film on the non-magnetic substrate, a hard carbon film on the ferromagnetic thin film, a modified layer of which atomic ratio of nitrogen/carbon is 0.8% or more, and of which thickness is less than 3 nm on the hard carbon film, and a lubricant layer on the modified layer, has excellent electromagnetic conversion characteristic, running stability, durability, and weatherability.

Magnetic recording medium and its manufacturing method

A protection film and a lubricant layer of monomers are formed successively on a ferromagnetic metal thin film formed on a nonmagnetic substrate or on a base of sliding member. Then, the lubricant layer is irradiated with radicals or atomic gas in the plasma discharge or with an electron beam to form graft polymers in the lubricant layer, and the protection film and the lubricant layer are bonded chemically. Thus, the reliability of a magnetic recording medium and a sliding member can be improved.

Method of manufacturing a magnetic recording medium including forming a

Magnetic recording medium having a ferromagnetic metal thin film, a dry

A magnetic recording media comprising a non-magnetic substrate, a ferromagnetic thin film on the non-magnetic substrate, a hard carbon film on the ferromagnetic thin film, a modified layer of which atomic ratio of nitrogen/carbon is 0.8% or more, and of which thickness is less than 3 nm on the hard carbon film, and a lubricant layer on the modified layer, has excellent electromagnetic conversion characteristic, running stability, durability, and weatherability.

Method of manufacturing a magnetic recording medium

A magnetic recording medium comprising a back coating layer formed on a surface reverse to a magnetic layer and a carbonaceous film which is formed on the back coating layer and contains fluorine atoms and silicon atoms and/or nitrogen atoms and in which a concentration of fluorine atoms decreases in a depth direction from a surface of the carbonaceous film, while a concentration of the silicon and/or nitrogen atoms increases in the depth direction from the surface of the carbonaceous film, which recording medium has improved running stability, durability and weatherability while electromagnetic conversion characteristics are maintained.

Method for forming film by plasma CVD

A magnetic recording medium comprising a non-magnetic substrate, a ferromagnetic metal film formed on said non-magnetic substrate, a carbon film which is formed on said ferromagnetic metal film and in which a concentration of at least one element selected from the group consisting of silicon, phosphorus, sulfur, tin and indium is or concentrations of boron and at least one element selected from the group consisting of tin and indium are decreased in a depth direction from the surface of said carbon film, and a lubricant layer formed on said carbon film, which medium has improved running durability and corrosion resistance.

Magnetic recording medium having improved running time and corrosion

With the use of a novel method in which after a magnetic recording medium carrying a ferromagnetic metal thin film is heated, a protective layer is developed on the ferromagnetic metal thin film by a known plasma CVD technique while an out gas from the magnetic recording medium being eliminated by absorption, another method in which a ferromagnetic metal thin film and a protective layer are formed in succession within a vacuum chamber, or a further method in which after a non-magnetic substrate is heated, a ferromagnetic metal thin film and a protective layer are formed in succession within a vacuum chamber while an out gas from the non-magnetic substrate and the ferromagnetic metal thin film being eliminated by absorption, the atomic ratio of the hydroxyl group to a primary component metal element contained in the ferromagnetic metal thin film can be decreased at the interface between the ferromagnetic metal thin film and the protective layer.

Magnetic recording medium and method of producing the same

In making a magnetic recording medium, a diamond-like carbon film is formed stably with high product efficiency such as 200 .ANG./sec, without occurrence of irregular discharge, and improved still durability and reduced head contamination are achieved by utilizing a.c. plasma discharge or a.c. plasma discharge superimposed by d.c. power and the lubricant film.

Magnetic recording medium having a carbon protective layer and partially

A magnetic recording medium comprising: a non-magnetic substrate; a ferromagnetic metal thin film provided on the non-magnetic substrate; a filmlike first carbon layer provided on the ferromagnetic metal thin film; and a hard and amorphous second carbon layer provided on the first carbon layer; the first and second carbon layers having first and second Raman spectra based on Raman spectrophotometry, respectively; assuming that when each of the first and second Raman spectra is decomposed into a first band of Gaussian function having a peak in the vicinity of 1380 cm.sup.-1 and a second band of Gaussian function having a peak in the vicinity of 1550 cm.sup.-1 in X-Y rectangular coordinates with an X-axis expressed in cm.sup.-1 and a Y-axis indicative of spectral intensity, a ratio of an area enclosed by the first band and the X-axis to an area enclosed by the second band and the X-axis represents 'relative intensity', the first carbon layer has a relative intensity of 2 to 20, while the second carbon layer has a relative intensity of 0.8 to 3, a Vickers hardness of not less than 1,000 kg/mm.sup.2 and a thickness of 50 to 300 .ANG..

Magnetic recording medium comprising a ferromagnetic metal film and two

A method of forming a film on a substrate by plasma CVD, comprising the steps of: providing a discharge tube in a vacuum chamber; providing a partition wall around the discharge tube; evacuating space between the discharge tube and the partition wall to vacuum; providing the substrate at a position confronting the discharge tube; and effecting plasma discharge in the discharge tube.

Method of forming film by plasma CVD

A method of producing a magnetic recording medium comprises the steps of heating in vacuum a magnetic recording medium produced by forming a ferromagnetic metal-film-type recording medium onto a non-magnetic substrate and of forming, immediately after heating, a protective layer on the magnetic recording medium by a plasma CVD method. A production apparatus for carrying out this method comprises a feeding apparatus for feeding a magnetic recording medium with a ferromagnetic thin film formed on a non-magnetic substrate, a plasma CVD apparatus, disposed in the path of this feeding apparatus, for forming a protective layer, and a heating apparatus disposed just before this plasma CVD apparatus in the feeding path.

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Hirakata, Japan

Mikio Murai