Abstract: A magnetic recording material, and, more particularly, a high density magnetic recording material is disclosed having an aromatic polyamide support in which the adhesion between the support and the magnetic recording layer is improved by an undercoating of an alcohol-soluble polyamide resin.

Abstract: Corrosion resistant ferromagnetic metal powders in which a volatile corrosion inhibitor is adsorbed on at least a part of the surface of ferromagnetic metal powders having an average particle size of 1000 A or less are disclosed. A method of preparing the corrosion resistant ferromagnetic metal powders is also disclosed.

Abstract: This invention relates to a magnetic recording medium comprising a non-magnetic support and magnetic layer provided thereon containing a ferromagnetic metal powder, the magnetic layer having a multilyaer structure consisting of a lower layer containing acicular grains obtained by dry process reduction and an upper layer containing chain-like grains obtained by wet process reduction, the upper layer being provided on the lower layer. This magnetic recording medium is particularly suitable for high density recording.

Abstract: A process for producing a ferromagnetic powder comprising effecting the oxidation-reduction reaction in an aqueous solution of a metal salt containing at least Fe and capable of forming a ferromagnetic substance, by the use of at least one member selected from the group consisting of boron hydride compound and a derivative thereof, and in the presence of a Ti compound.

Abstract: In a magnetic recording member comprising a non-magnetic support having provided thereon a magnetic layer comprising finely divided ferromagnetic powders dispersed in a binder, in which the binder comprises about 10 to about 70 wt% of (a) a polyester-polyurethane resin and about 30 to about 90 wt% of (b) a synthetic non-drying oil modified alkyd resin and (c) a polyisocyanate, wherein the molar ratio of the isocyanate groups present in the polyisocyanate (c) to the hydroxyl groups present in the synthetic non-drying oil-modified alkyd resin (b) ranges from about 0.8:1 to about 2.0:1. The binder system in accordance with the present invention provides excellent magnetic properties, particularly improved squareness ratio and 5 MHz output. The binder system of the present invention also enables the use of finely divided ferromagnetic alloy powders, with excellent magnetic properties being maintained when magnetic recording members are produced therefrom.

Abstract: A process for producing a ferromagnetic powder comprising injecting a stream of an aqueous solution of a metal salt capable of forming a ferromagnetic substance and a stream of solution containing a reducing material for mixing into a reaction chamber such that the two solutions impinge upon one another causing an oxidation-reduction reaction between them to occur, and applying a magnetic field of 50 oe or more to the particles produced by the oxidation-reduction reaction for the period during which the particles become ferromagnetic particles after going through a superparamagnetic state and an apparatus for use in the practice of the above process comprising a reaction vessel, at least one nozzle for injecting each of a solution of a metal salt and a solution containing a reducing material into the reaction vessel and a magnet for producing a magnetic field in the reaction vessel with the nozzles being open to the magnetic field and positioned so that the solution of the metal salt and the solution of the r

Abstract: A magnetic recording material, which comprises a non-magnetic support having thereon a magnetic layer containing ferromagnetic powder dispersed in a binder, with the magnetic layer containing an organic silicone compound represented by the following general formula (I); ##STR1## wherein R, R' and R", which may be the same or different, each has 7 to 21 carbon atoms and represents an alkyl group, an alkenyl group, an alkadienyl group, an alkatrienyl group or an alkatetraenyl group, m represents an integer of 1 to 100; n represents an integer of 0 to 250; and m+n.ltoreq.300 and m.gtoreq.n/5.

Abstract: A magnetic recording member comprising a non-magnetic support having thereon a magnetic layer of a ferromagnetic powder dispersed in a binder, wherein the magnetic layer contains an organic silicone compound represented by the formula (I): ##STR1## wherein R and R', which may be the same or different, each is a saturated or unsaturated hydrocarbon group containing 7 to 21 carbon atoms, and n is an integer of 0 to 50.

Abstract: A ferromagnetic metal powder having a narrow distribution of coercive force produced by reducing a salt of a metal capable of forming a ferromagnetic material as an aqueous solution thereof, where the reducing reaction is carried out while maintaining the temperature of the aqueous solution during and/or after the reduction reaction at about 20.degree. C higher than the temperature or less of the aqueous solution at the immediate beginning of the reduction reaction.

Abstract: A method of producing a magnetic material comprising reducing in a solution of a salt of a metal capable of forming a ferromagnetic material with a reducing agent comprising at least one of a borohydride and a derivative thereof, in a solution containing a hydroxide ion concentration of at least about 0.001N and not higher than about 0.6N.

Abstract: An improved method of making a magnetic recording material comprises providing a ferromagnetic metal thin layer which has uniaxial anisotropy in any direction on a web by means of plating.A plating solution is jetted onto the web through holes in a conveying pipe set in a plating bath. The web is then moved from the vicinity of the conveying pipe by the spouting force of the plating solution, and then conveyed along a helical path about the conveying pipe without contacting the surface of conveying pipe. Plating occurs while applying a magnetic field to the web.

Abstract: This invention relates to a magnetic recording substance comprising a support and a magnetic layer containing a ferromagnetic metal powder of liquid phase reduction type in a binder, the ferromagnetic metal powder being obtained by mixing an aqueous slurry containing the ferromagnetic metal powder with an organic solvent capable of forming a minimum boiling azeotropic mixture with water and subjecting the mixture to distillation to remove the water.

Abstract: A ferromagnetic metal powder obtained by a reducing reaction of wet process or dry process is brought into contact with a solution containing phosphate ion. The ferromagnetic metal powder treated in this way is favorably used for magnetic recording media, in particular, suitable for high density recording.

Abstract: A process for producing a ferromagnetic metal powder comprising treating a ferromagnetic metal powder produced by a solution reduction process with an aqueous solution containing at least one anionic surface active agent.

Abstract: Ferromagnetic powders comprising cobalt and/or nickel are produced by reducing cobalt and/or nickel salts in an aqueous solution containing hypophosphite ions while applying a magnetic field.

Abstract: A ferromagnetic material having a high coercive force and good squareness ratio prepared by mixing an aqueous solution at least containing a salt of a metal capable of forming a ferromagnetic material with a solution of a reducing agent containing at least one of a boron hydride compound or a derivative thereof to perform an oxidation-reduction reaction, wherein the mixing of the solutions is after adjusting the pH of the aqueous solution of the metal salt to about 3.0 or less, and the pH of the reaction mixture at the end of the reaction is adjusted to at least about 3.0 or higher.

Abstract: A magnetic recording medium for high density recording comprising a support having thereon a magnetic recording layer comprising a ferromagnetic metal powder of the Fe-Co-Cr-B system and having a coercive force of about 700 to 1500 orsteds in the oriented direction of the magnetic substance and a residual magnetic flux density of about 1500 gauses or more, the residual magnetic flux density of which after storage for 160 hours under the conditions of a temperature of 60.degree. C and 90%RH is 85% or more of the initial value thereof before storage under these conditions in a binder. The magnetic recording medium is especially suitable for high density recording, having sufficient sensitivity and excellent resistance.

Abstract: A powdery ferromagnetic metal material for a magnetic recording medium containing at least Fe, B and Pb as the main component and a process for producing a powdery ferromagnetic metal material comprising reducing a metal salt capable of forming a ferromagnetic substance and containing at least Fe in an aqueous solution thereof using a borohydride compound and/or derivative thereof in the presence of a Pb compound.

Abstract: A ferromagnetic powder which contains at least Fe--B or Fe--Co--B with the surface of the powder having thereon a layer of Cr or a layer mainly consisting of Cr and a method of preparing the ferromagnetic powder comprising reducing a metal salt capable of forming a ferromagnetic powder containing at least Fe or Fe-Co in an aqueous solution thereof with one or more borohydride compounds or derivatives thereof and after the reduction is initiated adding an aqueous solution containing Cr ion or an anion containing Cr.

Abstract: A magnetic recording medium for high density recording comprising a support having thereon a magnetic recording layer comprising a ferromagnetic metal powder of the Fe-Co-Cr-B system and having a coercive force of about 700 to 500 oersteds in the oriented direction of the magnetic substance and a residual magnetic flux density of about 1500 gausses or more, the residual magnetic flux density of which after storage for 160 hours under the conditions of a temperature of 60.degree.C and 90%RH is 85% or more of the initial value thereof before storage under these conditions in a binder. The magnetic recording medium is especially suitable for high density recording, having sufficient sensitivity and excellent resistance.