The disclosure discloses a method for preparing a -Fe.sub.4N soft magnetic material by using liquid nitrogen through high-speed ball milling, and belongs to the field of the soft magnetic material. According to the method of the disclosure, high energy in the liquid nitrogen is used for obtaining a nanometer material Fe.sub.xN with a nitrogen atom supersaturation degree through cryogrinding. At a low temperature, the material is very brittle, and a surface volume ratio is very high, so that a content of nitrogen atoms adsorbed on a surface of a sample is as high as 22%. Through 300 C. post-annealing, -Fe.sub.4N is directly obtained from -Fe through phase change, so that a nanometer crystal -Fe.sub.4N soft magnetic material is prepared. The method of the disclosure has the advantages that an operation is simple and convenient, the cost is low, the large-scale industrialized production can be realized, and the method belongs to a novel alternative method for preparing a high-grade soft magnetic material with ideal magnetism. The -Fe.sub.4N soft magnetic material prepared by the method of the disclosure has the advantages of high Ms, low coercivity and high surface resistivity, and can be used for a transformer and an inductor operated in a high-frequency semiconductor switch.

A sintered magnet body (R.sub.aT.sup.1.sub.bM.sub.cB.sub.d) coated with a powder mixture of an intermetallic compound (R.sup.1.sub.iM.sup.1.sub.j, R.sup.1.sub.xT.sup.2.sub.yM.sup.1.sub.z, R.sup.1.sub.iM.sup.1.sub.jH.sub.k), alloy (M.sup.1.sub.dM.sup.2.sub.e) or metal (M.sup.1) powder and a rare earth (R.sup.2) oxide is diffusion treated. The R.sup.2 oxide is partially reduced during the diffusion treatment, so a significant amount of R.sup.2 can be introduced near interfaces of primary phase grains within the magnet through the passages in the form of grain boundaries. The coercive force is increased while minimizing a decline of remanence.

A sintered magnet body (R.sub.aT.sup.1.sub.bM.sub.cB.sub.d) coated with a powder mixture of an intermetallic compound (R.sup.1.sub.iM.sup.1.sub.j, R.sup.1.sub.xT.sup.2.sub.yM.sup.1.sub.z, R.sup.1.sub.iM.sup.1.sub.jH.sub.k), alloy (M.sup.1.sub.dM.sup.2.sub.e) or metal (M.sup.1) powder and a rare earth (R.sup.2) oxide is diffusion treated. The R.sup.2 oxide is partially reduced during the diffusion treatment, so a significant amount of R.sup.2 can be introduced near interfaces of primary phase grains within the magnet through the passages in the form of grain boundaries. The coercive force is increased while minimizing a decline of remanence.

A sintered magnet body (R.sub.aT.sup.1.sub.bM.sub.cB.sub.d) coated with a powder mixture of an intermetallic compound (R.sup.1.sub.iM.sup.1.sub.j, R.sup.1.sub.xT.sup.2.sub.yM.sup.1.sub.z, R.sup.1.sub.iM.sup.1.sub.jH.sub.k), alloy (M.sup.1.sub.dM.sup.2.sub.e) or metal (M.sup.1) powder and a rare earth (R.sup.2) oxide is diffusion treated. The R.sup.2 oxide is partially reduced during the diffusion treatment, so a significant amount of R.sup.2 can be introduced near interfaces of primary phase grains within the magnet through the passages in the form of grain boundaries. The coercive force is increased while minimizing a decline of remanence.

Disclosed herein is a method comprising disposing a container containing a metal and/or ferromagnetic solid and abrasive particles in a static magnetic field; where the container is surrounded by an induction coil; activating the induction coil with an electrical current, to heat up the metallic or ferromagnetic solid to form a fluid; generating sonic energy to produce acoustic cavitation and abrasion between the abrasive particles and the container; and producing nanoparticles that comprise elements from the container, the metal and/or the ferromagnetic solid and the abrasive particles. Disclosed herein too is a composition comprising first metal or a first ceramic; and particles comprising carbides and/or nitrides dispersed therein. Disclosed herein too is a composition comprising nanoparticles comprising chromium carbide, iron carbide, nickel carbide, -Fe and magnesium nickel.

Techniques are disclosed for milling an iron-containing raw material in the presence of a nitrogen source to generate anisotropically shaped particles that include iron nitride and have an aspect ratio of at least 1.4. Techniques for nitridizing an anisotropic particle including iron, and annealing an anisotropic particle including iron nitride to form at least one -Fe.sub.16N.sub.2 phase domain within the anisotropic particle including iron nitride also are disclosed. In addition, techniques for aligning and joining anisotropic particles to form a bulk material including iron nitride, such as a bulk permanent magnet including at least one -Fe.sub.16N.sub.2 phase domain, are described. Milling apparatuses utilizing elongated bars, an electric field, and a magnetic field also are disclosed.

Techniques are disclosed for milling an iron-containing raw material in the presence of a nitrogen source to generate anisotropically shaped particles that include iron nitride and have an aspect ratio of at least 1.4. Techniques for nitridizing an anisotropic particle including iron, and annealing an anisotropic particle including iron nitride to form at least one -Fe.sub.16N.sub.2 phase domain within the anisotropic particle including iron nitride also are disclosed. In addition, techniques for aligning and joining anisotropic particles to form a bulk material including iron nitride, such as a bulk permanent magnet including at least one -Fe.sub.16N.sub.2 phase domain, are described. Milling apparatuses utilizing elongated bars, an electric field, and a magnetic field also are disclosed.

A reduction treatment agent made of a powder with a particle size within a range of 1500 to 3000 mesh, the powder containing: 20 to 40 parts of a mixed-oxide powder containing magnesium oxide and zinc oxide; and 60 to 80 parts of an organic acid powder containing calcium, ascorbic acid, citric acid and salt. The reduction treatment agent may further contain one to six kinds of metal powder selected from the group of copper, molybdenum, nickel, cobalt, iron and aluminum, each in an amount of one part. Due to this configuration, the reduction treatment agent can be easily mixed with various substances when added to those substances. Even if the target substance is not water, the agent can entirely and uniformly change that substance into a reduced state. Additionally, the reduction treatment agent can act as a surfactant, and therefore, can be used as cosmetics or food.

A sintered magnet body (R.sub.aT.sup.1.sub.bM.sub.cB.sub.d) coated with a powder mixture of an intermetallic compound (R.sup.1.sub.iM.sup.1.sub.j, R.sup.1.sub.xT.sup.2.sub.yM.sup.1.sub.z, R.sup.1.sub.iM.sup.1.sub.jH.sub.k), alloy (M.sup.1.sub.dM.sup.2.sub.e) or metal (M.sup.1) powder and a rare earth (R.sup.2) oxide is diffusion treated. The R.sup.2 oxide is partially reduced during the diffusion treatment, so a significant amount of R.sup.2 can be introduced near interfaces of primary phase grains within the magnet through the passages in the form of grain boundaries. The coercive force is increased while minimizing a decline of remanence.

Disclosed herein is a method comprising disposing a container containing a metal and/or ferromagnetic solid and abrasive particles in a static magnetic field; where the container is surrounded by an induction coil; activating the induction coil with an electrical current, to heat up the metallic or ferromagnetic solid to form a fluid; generating sonic energy to produce acoustic cavitation and abrasion between the abrasive particles and the container; and producing nanoparticles that comprise elements from the container, the metal and/or the ferromagnetic solid and the abrasive particles. Disclosed herein too is a composition comprising first metal or a first ceramic; and particles comprising carbides and/or nitrides dispersed therein. Disclosed herein too is a composition comprising nanoparticles comprising chromium carbide, iron carbide, nickel carbide, -Fe and magnesium nitride.