Abstract: In a magnetic recording medium comprising a non-magnetic support and two or more magnetic recording layers containing ferromagnetic particles dispersed in a non-magnetic binder, the ferromagnetic particles of the outermost magnetic layer are given a main magnetic anisotropy by a magnetic annealing treatment and the direction of the magnetic anisotropy is vertical to the recording surface. Thus, the vertical magnetization recording is improved.

Abstract: A magnetic recording medium which is characterized by a lubricant present in channels diagonally extending through a magnetic metal thin film having a columnar structure formed by vapor deposition; this medium possesses improved running properties and abrasion resistance which last for an extended period of time.

Abstract: A method for preparing ferromagnetic metal particles is disclosed. The method involves dehydrating oxyhydroxide particles comprised mainly of iron in a nonreducing gas under heating at a temperature of not more than 500.degree. C. to form oxide particles, providing silicon compounds on the surface of oxide particles, and reducing the oxide particles in a reducing gas under heating. The ferromagnetic metal particles provided have good acicular shape and a large specific surface area.

Abstract: A magnetic recording medium which comprises a non-magnetic support having thereon a magnetic layer containing plate-shaped magnetic particles which have axes of easy magnetization perpendicular to their respective plate planes dispersed in a binder, the magnetic particles each having a multiple magnetic domain structure and having a particle diameter equal to or longer than the recorded effective shortest wavelength.

Abstract: A method for preparing a magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer containing plate-shaped ferromagnetic fine particles oriented perpendicular to a plane of the surface of the support, the process comprising the steps of:coating the non-magnetic support with a coating composition wherein ferromagnetic fine particles are dispersed in a solution comprised of a compound polymerizable by radiation with electron beams and a solvent, said particles being plate-shaped and having an axis of easy magnetization perpendicular to a plane of the plate-shaped particles;orienting the ferromagnetic fine particles perpendicular to the surface of support while the coating composition is undried;radiating the composition with electron beams; anddrying the composition by removing the solvent.

Abstract: In a method of making a magnetic recording medium by causing a flow of vapor obtained by evaporating a magnetic metal deposition material to impinge and deposit on a moving substrate at an oblique angle with respect to the moving substrate, the substrate is moved so that the incident angle of the vapor flow with respect to the substrate continuously changes from the maximum incident angle to the minimum incident angle, and an oxidizing gas is introduced in the vicinity of the substrate and near the maximum incident angle portion or the minimum incident angle portion of the vapor flow during the formation of a thin ferromagnetic film on the substrate. The maximum incident angle is preferably between 60.degree. and 90.degree., and the minimum incident angle between 30.degree. and 75.degree..

Abstract: Ferromagnetic metal particles are disclosed, which have a silane compound on the surface thereof. The silane compound is represented by the formula:R.sub.n --Si--(OR').sub.4-nwherein R and R' each represent an alkyl group and n represents 2 or 3. The ferromagnetic metal particles have excellent oxidation stability and corrosion resistance. Furthermore, the ferromagnetic metal particles have good dispersibility within a binder when used in connection with producing a magnetic recording medium.

Abstract: A magnetic recording medium is described wherein a layer comprising mainly a polyurethane resin, vinylidene chloride copolymer, or a cellulose derivative is formed on the surface of a vapor-deposited ferromagnetic metal layer on a substrate.

Abstract: An apparatus for manufacturing a magnetic recording medium using vacuum-deposition from an evaporated metal source having a very high efficiency and uniform deposition. The support onto which the magnetic film is to be evaporated is guided and conveyed along a curved path above a molten metal evaporating source at a substantially constant speed. The curved path is shaped such that evaporated metal flow lines connecting a central point on the evaporation surface of the molten metal in the evaporating source to corresponding intersection points on the support form the same angle of incidence with respect to the longitudinal direction of the support for all positions along the support where the film is to be deposited. Endless belt structures including guide rollers and magnets are used to form rising and falling paths for conveying the support along the desired curved path.

Abstract: A magnetic recording medium which comprises a non-magnetic support having thereon two or more magnetic layers comprising magnetic particles in a binder. The magnetic layer(s) other than the topmost layer comprises needle-shaped magnetic particles. The topmost layer comprises plate-shaped magnetic particles which have axes of easy magnetization perpendicular to the individual plate planes and the plate planes are oriented substantially parallel to the surface of the magnetic layer.

Abstract: A magnetic recording medium is described having formed on a non-magnetic base at least two magnetic layers, each of the magnetic layers comprising ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles in the outermost layer have an average length of 0.3.mu. or less and a length to width ratio of greater than 1/1 but not greater than 3/1, and the ferromagnetic particles in an underlying layer have a length to width ratio of more than 3/1.

Abstract: A magnetic recording medium is described having formed on a non-magnetic base at least two magnetic layers, each of the magnetic layers comprising ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles in the outermost magnetic layer are substantially cubic particles and have a side length of 0.3.mu. or less, and the ferromagnetic particles in an underlying magnetic layer are acicular particles.

Abstract: A ferromagnetic powder and process for producing it are disclosed. The process involves providing reducing a nickel-doped or nickel-coated iron compound in a reducing gas to provide a reduced metal powder including nickel in an amount of 3 to 30 atomic % based on the atomic % of iron present in the reduced metal powder, and treating the reduced metal powder with an organic metal powder. The resulting ferromagnetic metal powder has excellent stability with respect to oxidation and has a high saturation magnetization.

Abstract: A magnetic recording medium comprising a magnetic layer on one surface of a non-magnetic base and a back coating on the other surface thereof which is not thicker than 2.mu. and which contains inorganic particles and a binder is disclosed. The inorganic particles have an average size between 0.02 and 5.mu. and a Mohs hardness of 2.5 to 9.0, and the surface of the back coating has a center line average roughness (Ra) of 0.024 or less and the surface of the magnetic layer has a center line average roughness (Ra) of 0.02.

Abstract: A magnetic recording medium comprising a substrate, a thin magnetic metal film having spaced-apart columnar grains deposited on the substrate, and a crosslinked organic polymer formed from a polymerizable organic compound and a curing agent in the spaces between the columnar grains and integrated therewith. The medium is prepared by impregnating the spaces between the columnar grains with a polymerizable organic compound and a curing agent and curing them in the spaces by the crosslinking reaction.

Abstract: A magnetic recording medium manufacturing device in which a flexible belt-shaped support is conveyed above a molten metal vaporizing source substantially at a constant speed while a magnetic film is formed on a surface of the support by vacuum deposition. The support is guided by transporting means such that the support is curved above the molten metal vaporizing source along a path wherein metal vapor flow lines connecting the center of the molten metal vaporizing source to points on the surface of the support form a constant angle of incidence with the longitudinal direction of the support. An adjusting mechanism is provided to change the angle of incidence by moving the transporting means along lines parallel to the metal vapor flow lines.

Abstract: A magnetic recording medium comprising a substrate, a thermoplastic prime coat provided thereon, and a ferromagnetic metal layer having columnar grains which at least partially penetrate into the prime coat from the top thereof and are integrated therewith. The medium is prepared by applying a prime coat onto a substrate, forming a magnetic metal layer having columnar grains by vapor deposition, and then heating and pressing the obtained combination.

Abstract: A magnetic recording medium is described comprising a first layer comprising a magnetic iron oxide powder dispersed in a binder formed on a nonmagnetic support, a second layer formed on the first layer comprising a ferromagnetic metal powder dispersed in a binder, and having a greater coercive force than the first layer, and a third layer comprising a thin ferromagnetic metal film formed on the second layer in a thickness of from 0.01.mu. to 0.5.mu..

Abstract: A method and apparatus for manufacturing a magnetic recording medium using vacuum-deposition from an evaporated metal source having a very high efficiency and uniform deposition. The support onto which the magnetic film is to be evaporated is guided and conveyed along a curved path above a molten metal evaporating source at a substantially constant speed. The curved path is shaped such that evaporated metal flow lines connecting a central point on the evaporation surface of the molten metal in the evaporating source to corresponding intersection points on the support form the same angle of incidence with respect to the longitudinal direction of the support for all positions along the support where the film is to be deposited. Endless belt structures including guide rollers and magnets are used to form rising and falling paths for conveying the support along the desired curved path.

Abstract: A magnetic recording material having superior abrasion resistance and thermal stability is produced by coating a magnetic coating composition consisting essentially of aqueous emulsions of at least two resin binders capable of reacting with each other upon mixing, and being present therein in the separated state, and a ferromagnetic powder on a non-magnetic support, drying the coating, and curing the resulting magnetic recording layer where drying is insufficient to effect curing. Hazards ascribable to the use of organic solvents in conventional techniques can be obviated by this invention.