National Research Institute for Metals

Nisshin Steel Co., Ltd.

Masahiro Uda

Satoru Ohno

Yoshikazu Morita

Hideo Okuyama

Katsuhisa Ohsaki

Tsutomu Hoshi

Katsuhisa Oosaki

Tutomu Hoshi

An intermetallic compound such as Nb.sub.3 Al exhibits the phenomenon of self-disintegration, when hydrogen is adsorbed in the intermetallic compound. This self-disintegration is used for the pulverization of the intermetallic compound material. The material is autogeneously pulverized into very fine particles only by adjusting an atmosphere to which the material is exposed, since the pulverizing reaction occurs between hydrogen existent in the atmosphere and the active surface of the intermetallic compound. The pulverized intermetallic compound having irregular shapes and large specific surface area is useful in various technical fields, e.g. as a superconductive material, a heat-resistant material, a magnetic body or a hydrogen-absorbing material.

Production of powdery intermetallic compound having very fine particle

Method for the production of aluminum nitride-based sintered products

A process for producing ultrafine particles of a ceramic, which comprises heating a ceramic having substantially the same components as the final ultrafine ceramic particles, a metal constituting the metal component of the final ultrafine ceramic particles, a mixture of said ceramic with said metal or carbon, or a mixture of said metal with carbon by an arc plasma or a high frequency induction plasma generated in hydrogen, nitrogen, oxygen, a gaseous mixture of hydrogen and nitrogen, or a gaseous mixture of nitrogen and oxygen.

Process for producing ultrafine particles of ceramics

A process for producing a mixed ultrafine powder, which comprises reacting at least two metals or ceramics in the molten state with hydrogen, nitrogen, oxygen, a mixture of hydrogen and nitrogen or a mixture of nitrogen and oxygen. Each said gas or gaseous mixture being activated with a hot plasma, in an atmosphere of hydrogen gas, nitrogen gas, oxygen gas, a gaseous mixture of hydrogen and nitrogen, a gaseous mixture of nitrogen and oxygen, or a gaseous mixture of any of said gases with an inert gas under a pressure of 50 torr to 3 atmospheres to form ultrafine particles of said at least two metals or ceramics afloat in the atmospheric gas, and thereafter mixing the floating ultrafine particles of the metals or ceramics by a gas current.

Process for producing mixed ultrafine powder of metals or ceramics

An apparatus for producing a particulate metal or alloy having a diameter of less than 5 microns by the reaction of a molten metal or alloy with activated hydrogen. The apparatus has (1) a metal melting hearth for melting a starting metal or alloy placed thereon and supporting the molten metal or alloy, (2) a discharge electrode positioned above, and opposite to, the metal or alloy placed on the melting hearth, (3) a closed vessel for containing the melting hearth and the discharge electrode, and (4) a gas inlet port in the wall of the closed vessel for introducing hydrogen or a hydrogen-containing gas into the vessel. The apparatus includes a device for quickly moving fine particles of the metal or alloy generated from the molten metal or alloy away from the vicinity of the molten metal by means of a current of hydrogen or a hydrogen-containing gas constituted by a suction duct for sucking a gas in the vicinity of the molten metal or alloy and withdrawing it out of the vessel and which extends into the vessel through the vessel wall and opens in the vicinity of the molten metal or alloy on the melting hearth; or a device for sending hydrogen or a hydrogen-containing gas into the closed vessel so as to form a turning flow of hydrogen or the hydrogen-containing gas moving downwardly from above the molten metal on the melting hearth or upwardly from below the molten metal. The improved apparatus also includes a trap for collecting the fine metal particles connected to the suction duct, a gas outlet or a gas passage, and a gas cooler provided upstream of the trap. The apparatus of this invention makes possible the production of fine particles of a metal or alloy having a narrow particle size distribution with a high recovery ratio.

Apparatus for producing fine metal particles

A process for producing fine particles of a metal or alloy, which comprises contacting a molten metal or alloy with activated hydrogen gas thereby to release fine particles of the metal or alloy having a diameter of less than 10 microns from the molten metal or alloy.

Growing community of inventors

Tokyo, Japan

Masahiro Uda