Abstract: Composite magnetic compacts having good conductivity and excellent mechanical and magnetic properties and their forming methods. The composite magnetic compacts are basically made by forming mixtures consisting essentially of 1 to 50 percent by weight of a magnetic powder and the remaining percentage of a powder of superplastic Zn-22A1 alloy. A drop in the strength of the compacts that occurs when the mixing percentage of the magnetic powder increases is made up for by the impregration of plastic in the compacts or the simpler addition of a plastic power to the mixture of the powders of magnetic material and superplastic Zn-22A1 alloy. The forming methods of the composite magnetic compacts are carried out at different temperatures and under different conditions depending on the composition of the powder mixtures and so on.

Abstract: To obtain an anticorrosive Fe-B-R type permanent magnet; in particular, to reduce deterioration rate of the initial magnetic properties below 10% after the magnet has been kept at 80.degree. C. in 90% relative humidity for 500 hours, the surface of the sintered permanent magnet is coated with metallic coating film layers of at least one noble metal layer and at least one base metal layer disposed on the noble metal layer. Diffusion heat treatment further improves the adhesiveness of the coating film layers.

Abstract: Disclosed herein are electroconductive iron oxide particles having a volume resistivity less than 5.times.10.sup.6 .OMEGA.-cm, and comprising iron oxide particles selected from hematite and maghemite, and SnO.sub.2 particles containing Sb as a solid solution deposited on the surfaces of the iron oxide particles, and a process for producing the same.

Abstract: Disclosed herein are Ba-containing plate like magnetoplumbite type ferrite particles for magnetic recording having the composition of AO.n{(Fe.sub.1-X M.sub.X).sub.2 O.sub.3 } (wherein A represents Ba or Ba and Sr, M represents Zn and Ti, or Zn, Co and Ti, n=6.5-11.0, and x=0.05-0.25) and the change of coercive force of said particles at a temperature of 20.degree.-120.degree. C. in the range of -2.0 Oe/.degree.C. to +2.0 Oe/.degree.C., and magnetic recording media using the same.

Abstract: Disclosed herein is a process for producing electroconductive fibrous shaped-articles comprising the steps of:soaking water-absorptive fibrous shaped-articles in a palladium hydrosol containing a cationic surfactant, an anionic surfactant, a non-ionic surfactant or a mixture thereof, and after (i) drying the thus treated shaped-articles, (ii) washing the thus treated shaped-articles with water or (iii) washing the thus treated shaped-articles and then drying, subjecting the thus obtained, shaped-articles on which colloidal palladium is adsorbed to chemical plating, thereby obtaining the electroconductive fibrous shaped-articles of which fibers thereof are subjected to metallizing plating.

Abstract: Disclosed herein are hexagonal plate-like barium ferrite particles for magnetic recording, represented by the formula: BaFe.sub.12-x-y M.sub.x Ti.sub.y O.sub.19 wherein x and y are independently 0.6 to 1.2 and M is Co(II) or Co(II) and a divalent metal other than Co, having the width of the particle of 0.1 to 0.4 micrometer and a BET specific surface area (S) of 20 to 50 m.sup.2 /g, and showing a magnetization (M) of larger than 40 emu/g in a magnetic field of 10 KOe and a coercive force (Hc) of 500 to 1000 Oe, and a process for producing the same.

Abstract: Disclosed herein are plate-like barium ferrite particles having BET specific surface area of 20 to 70 m.sup.2 /g and average particle diameter of 0.05 to 0.3 .mu.m, and showing a magnetization of higher than 30 emu/g in a field of 10 kOe and coercive force of 300 to 1,000 Oe, represented by the formula BaCo.sub.x Ti.sub.x Fe.sub.12-2x O.sub.19 wherein x is 0.1 to 0.5, and a process for producing the same.

Abstract: Disclosed herein are plate-like barium ferrite particles for magnetic recording, comprising plate-like particles represented by the formula:BaFe.sub.12-2x M.sub.x Ti.sub.x O.sub.19wherein x is 0 to 1.2 and M represents Co (II) or Co (II) and a divalent metal ion other than Co (II), the surface of the plate-like particles being modified with magnetite represented by the formula:FeO.sub.y.Fe.sub.2 O.sub.3wherein y is over 0 and not more than 1, and a process for producing the same.

Abstract: Disclosed herein is a process for producing the plate-like barium ferrite particles represented by the formula (I):BaFe.sub.12-x-y M.sub.x Ti.sub.y O.sub.19 (I)wherein x and y are respectively 0.3 to 1.2 and M is a divalent metal selected from the group consisting of Co, Ni, Zn and Mn, which comprises autoclaving an aqueous highly alkaline suspension containing spinel particles represented by the formula: Fe.sub.12-x-y M.sub.x Ti.sub.y O.sub.16, wherein x, y and M are respectively the same as defined above, having an average particle size of less than 0.1 .mu.m and Ba ions at a temperature of 250.degree. to 330.degree. C., the atomic ratio of Ba to total amount of the metals being in a range from 1:8 to 1:10.

Abstract: Disclosed herein are the plate-like barium ferrite particles for use in magnetic recording, showing a specific surface area of 11 to 50 m.sup.2 /g, a value of magnetization of higher than 25 emu/g in a magnetic field of 10 KOe and a coercive force of 600 to 1100 Oe, and a process for producing the same.

Abstract: Barium ferrite particles of a coercive force of not more than 1,000 Oe suitable for use as a magnetic material for magnetic recording and a process for producing said particles are disclosed herein.

Abstract: Disclosed herein is a process for producing plate-like barium ferrite particles for magnetic recording, represented by the formula:BaFe.sub.12-x-y M.sub.x Ti.sub.y O.sub.19wherein x and y are independently not more than 1.2 and M is Co(II) or Co(II) and a divalent metal other than Co, which comprises adding a compound of Si(IV) to an aqueous highly alkaline suspension of ferric hydroxide containing Ti(IV), Ba(II) and Co(II) or Co(II) and a divalent metal other than Co as M(II), and autoclaving the resultant aqueous highly alkaline suspension of ferric hydroxide at the temperature of 200.degree. to 330.degree. C., thereby obtaining the plate-like barium ferrite particles having the thickness thereof controlled according to the atomic ratio of Si(IV) to Fe(III).

Abstract: Stabilization treatment of acicular ferromagnetic iron or iron-alloy fine particles against the oxidation thereof comprises the steps of (a) suspending acicular ferromagnetic iron or iron-alloy particles obtained by the reduction of acicular iron oxide which may contain Co or Ni in an aqueous alkaline solution having 0.01 to 18-N of hydroxyl ion concentration at a temperature of 5.degree. to 70.degree. C. while stirring the suspension in a non-oxidative atmosphere therethrough and thereby controlling the dissolution of ferrous ion from the surface of the acicular particles therein, (b) oxidizing the surface of the acicular particles in the resultant suspension by introducing an oxygen containing gas therein at a temperature of 60.degree. to 100.degree. C. to form dense and thin magnetite film on the surface of the acicular particles; and (c) drying the resultant particles in air at a temperature below 100.degree. C.

Abstract: A process for treating acicular magnetite containing Co to stabilize the magnetic properties thereof comprises the steps of heating acicular magnetite containing 0.1 to 2.5% by atom of Co with respect to Fe as starting material at a temperature in the range of 300 - 1000.degree. C in an inert gas atmosphere in which the partial pressure of oxygen is controlled at a value in the range of 0.001 - 1% by weight and for the time sufficient to homogenize the crystal structure of the acicular magnetite by thermal-diffusion of oxygen thereinto, and thereafter saturating the resultant acicular magnetite with oxygen by heating it at a temperature in the range of 40 - 100.degree. C in an oxygen rich atmosphere such as air.

Abstract: In the production of acicular ferromagnetic iron oxide of highly uniform particle size by oxidizing an iron (II) hydroxide suspension at a pH of at least 11 with an oxygen-containing gas to form acicular iron (III) oxide hydroxide, reducing and optionally further reoxidizing this into ferromagnetic iron oxide, the improvement which comprises providing the iron (II) hydroxide suspension with a water-soluble silicate in an amount of less than 1.7% by atom based on the amount of the iron (II) hydroxide in the suspension and calculated as the ratio of Si to Fe (II) while prior to the oxidation of the suspension with the oxygen-containing gas.

Abstract: The process for producing acicular magnetic metallic particle powder with improved magnetic properties which include the characteristic steps for producing the acicular particles of metal oxide with homogeneous and dense coats of crystalline silica and to thereby protect the particles from heat-damages during the reduction thereof under high temperatures.

Abstract: The present invention relates to a process for producing magnetic particle powder of acicular ferric oxide used for a magnetic recording material comprising (A) reducing acicular goethite particle powder to obtain acicular magnetite particle powder, (B) heating said acicular magnetite particle powder and thereby making the partial pressure of oxygen in said acicular magnetite particle powder reach the equilibrium value and (C) oxidizing said acicular magnetite particle powder to obtain gamma-hematite (maghemite) particle powder, and magnetic particle powder produced thereby.

Abstract: The processes for producing iron oxide products from a solution of ferrous salts selected from the group consisting of waste liquid containing ferrous salts and aqueous solution in which ferrous salts obtained from the waste liquid are dissolved, under the acid, wet and high ferrous concentration conditions. More particularly, the processes for purifying said waste liquids comprising the bivalent iron removing steps.