An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.

Disclosed is a method for preparing vanadium or vanadium alloy powder from a vanadium-containing raw material through a shortened process, including: calcinating a mixture of a vanadium-containing raw material and an alkali compound for oxidation to form a water-soluble vanadate; purifying the vanadate followed by vanadium precipitation to produce an intermediate CaV.sub.2O.sub.6 with high purity; dissolving CaV.sub.2O.sub.6 in a molten-salt medium together with other raw materials to form a uniform reaction system; and introducing a reducing agent to the system followed by separation, washing and drying to produce vanadium or vanadium alloy powder having a particle size of 50-800 nm and a purity of 99.0 wt % or more. The method can continuously process vanadium-containing raw materials to prepare vanadium or vanadium alloy powder.

A method for producing a water-atomized prealloyed powder with high cold press formability, includes the following steps: (a) preparing a 400 mesh semi-finished prealloyed powder; (b) controlling the semi-finished prealloyed powder to have a moisture content of 1 wt % to 2 wt % and an oxygen content of 0.6 wt % to 0.8 wt %, and then drying in a vacuum drying oven at 100 C. for 90 minutes to 120 minutes, so that a preliminary bond is produced between powder particles; and (c) reducing, annealing, crushing, and sieving an initially bonded powder particle. The powder is changed from a spheroidal shape to more complex shapes such as rice ear shape, grape shape, and satellite powder, which greatly improves the cold press formability of the prealloyed powder; the method only performs simple surface modification of the powder without changing other properties, and has wide applicability.

To provide a method for efficiently producing metal microparticles having a particle diameter of 1 m to 10 m, and a device for producing the same. A metal microparticle production method is used, which includes a particle generating step of generating primary particles by irradiating a metal lump in a solvent in a first tank with an ultrasonic wave, and a particle splitting step of irradiating the primary particles with an ultrasonic wave in a solvent in a second tank and splitting the primary particles to produce secondary particles. Further, a metal microparticle production device is used, which includes: a first tank that has a solvent and a metal lump; a first heating unit that heats the solvent in the first tank; a first ultrasonic vibrator that is disposed in the first tank and irradiates the metal lump with an ultrasonic wave to generate primary particles; a second tank that has the solvent and the primary particles; and a second ultrasonic vibrator that irradiates the primary particles with an ultrasonic wave to split the primary particles.

Alloys comprised of a refined microstructure, ultrafine or nano scaled, that when reacted with water or any liquid containing water will spontaneously and rapidly produce hydrogen at ambient or elevated temperature are described. These metals, termed here as aluminum based nanogalvanic alloys will have applications that include but are not limited to energy generation on demand. The alloys may be composed of primarily aluminum and other metals e.g. tin bismuth, indium, gallium, lead, etc. and/or carbon, and mixtures and alloys thereof. The alloys may be processed by ball milling for the purpose of synthesizing powder feed stocks, in which each powder particle will have the above mentioned characteristics. These powders can be used in their inherent form or consolidated using commercially available techniques for the purpose of manufacturing useful functional components.

An object of the present invention is to provide a Mn-based alloy exhibiting metamagnetism over a wide temperature range. A Mn-based alloy according to the present invention is a MnAl alloy having metamagnetism. The metamagnetism refers to a property in which magnetism undergoes transition from paramagnetism or antiferromagnetism to ferromagnetism by a magnetic field. In the MnAl alloy, an antiferromagnetic state is adequately stable, so that by imparting AFM-FM transition type metamagnetism (the type of metamagnetism undergoing transition from antiferromagnetism to ferromagnetism), it is possible to obtain metamagnetism over a wide temperature range, particularly, over a temperature range of 100 C. to 200 C.

A sintered magnet contains SmFeN-based crystal grains and has high coercivity; and a magnetic powder is capable of forming a sintered magnet without lowering the coercivity even if heat is generated in association with the sintering. A sintered magnet comprises a crystal phase composed of a plurality of SmFeN-based crystal grains and a nonmagnetic metal phase present between the SmFeN crystal grains adjacent to each other, wherein a ratio of Fe peak intensity I.sub.Fe to SmFeN peak intensity I.sub.SmFeN measured by an X-ray diffraction method is 0.2 or less. A magnetic powder comprises SmFeN-based crystal particles and a nonmagnetic metal layer covering surfaces of the SmFeN crystal particles.

Provided is a potassium titanate powder that can avoid safety and health concerns and concurrently, during use in a friction material, can give excellent frictional properties. A potassium titanate powder is a powder formed of bar-like potassium titanate particles having an average length of 30 m or more, an average breadth of 10 m or more, and an average aspect ratio of 1.5 or more, wherein the bar-like potassium titanate particles are represented by a composition formula K.sub.2Ti.sub.nO.sub.2n+1 (where n=5.5 to 6.5).

A system for creating a second quantity of sinterable powder particles which have sizes falling within a second size range, from a first quantity of sinterable powder particles having sizes falling within a first size range, and where the sizes of the powder particles in the second size range are all larger than those in the first size range. In one embodiment the system has a heating component responsive to a predetermined temperature/time heating profile, which heats the first quantity of powder particles using the temperature/time heating profile, to cause partial sintering of the powder particles, which creates a new plurality of powder particles which have an increased dimension. A movement component is incorporated to at least one of separate the new powder particles from remaining ones of the powder particles of the first quantity of powder particles, or to further process the new plurality of powder particles, such that the new plurality of powder particles represents the second quantity of sinterable powder particles.