Abstract: A process for producing a metal-base sinter, comprising sintering coated metal particles wherein the particles are prepared for sintering by the steps of: dispersing a powder of metal core particles in a gaseous atmosphere to form a mixture of a gas and particles in a powder of highly dispersed core particles; charging a precursor for the coat forming substance that has been formed via the vapor phase and/or a precursor for the coat forming substance in a vapor-phase state and the mixture of the gas and the powder of highly dispersed core particles that have a predetermined dispersity according to the average diameter of the core particles in a coating start region of a coating space; coating the surfaces of the core particles with the coat forming substance by allowing the precursor to contact and/or impinge against the core particles; shaping and sintering the thus coated metal core particles or a mixture containing them under appropriate sintering conditions.

Abstract: A process for producing a ceramic-base sinter, comprising sintering coated ceramic particles wherein the particles are prepared for sintering by the steps of: dispersing a powder of ceramic core particles in a gaseous atmosphere to form a mixture of a gas and particles in a powder of highly dispersed core particles; charging a precursor for the coat forming substance that has been formed via the vapor phase and/or a precursor for the coat forming substance in a vapor-phase state and the mixture of the gas and the powder of highly dispersed core particles that have a predetermined dispersity according to the average diameter of the core particles in a coating start region of a coating space; coating the surfaces of the core particles with the coat forming substance by allowing the precursor to contact and/or impinge against the core particles; shaping and sintering the thus coated ceramic core particles or a mixture containing them under appropriate sintering conditions.

Abstract: The present invention provides a powder classifier using a classification rotor capable of classifying powder with high efficiency and high accuracy. The classification rotor is attached to a rotating shaft as a body and rotatably supported in a casing. Within the classification rotor, a cavity is formed from the outer edge to the center and classifying vanes are provided around the circumference. The cavity is bent downwardly near the center with the lower end connected through a fine powder passage to a fine powder outlet. The outer edge of the classification rotor is connected to a coarse powder outlet. After feeding powder from a powder supply port, the powder is rotated by the classifying vanes such that coarse powder particles are taken out from the rough outlet by centrifugal force and fine powder particles are taken out by airflow from the fine powder outlet.

Abstract: The process for producing coated particles of the present invention is applicable to a process of producing coated particles by charging powder of core particles into the coating space and permitting a coat forming substance generated via a vapor phase or being in a vapor-phase state to contact against particles of the powder, and the process is characterized by dispersing powder of core particles having an average particle diameter of not more than 10 .mu.m and a particle size distribution of ((D.sub.M /5, 5D.sub.M), .gtoreq.90%) to adjust a dispersity .beta. to at least 70%, and contacting the dispersed powder of the core particles with the coat forming substance.

Abstract: A mechanical grinding apparatus of the present invention, which includes a rotor supported by a rotary shaft and having a plurality of grooves defined on the outer peripheral surface thereof and a liner inserted to the outside of the rotor so as to form a desired gap between the liner and the rotor and having a plurality of grooves defined on the inner peripheral surface thereof for grinding a substance to be ground in the gap, is characterized in that the grooves of at least one of the rotor and the liner incline in a direction preventing the flow of the substance to be ground with respect to a direction parallel with a rotary shaft. Since the mechanical grinding apparatus of the present invention can make a ground substance having a small particle size, no large particles mixed therein and a sharp particle size distribution width at a high efficiency, the grinding apparatus is preferably applicable to powder composed of resin or mainly composed of resin to be finely ground.

Abstract: Disclosed is a fiber of an organic, inorganic or metallic material or a simple substance wherein ultrafines of an inorganic or metallic material or a simple substance having an average particle diameter of 0.005-1 .mu.m are uniformly dispersed and deposited on 8-90% of the surface in a single layer. The fiber is produced by exposing a fiber of an organic, inorganic or metallic material or a simple substance to a gaseous stream forming ultrafines of an inorganic or metallic material or a simple substance by a vapor phase process, thereby contacting said ultrafines in the gaseous stream with said fiber in a state wherein the ultrafines are still active. The treated fiber is useful as a reinforcing material for a fiber reinforced composite.

Abstract: A powder of diamond or high-pressure phase boron nitride core particles charged into a coating space as it is dispersed, and a precursor of a coat forming substance allowed to contact and/or impinge against the particles in the powder of core particles so that their surfaces are covered with the coat forming substance, thereby preparing coated diamond or high-pressure phase boron nitride particles which are subsequently sintered. The thusly produced diamond of high-pressure phase boron nitride sinter is composed of coated core particles of high performance that are superhard, uniform, dense and sintered firmly, and which have a controlled microstructure.

Abstract: A particle of an inorganic or metallic material which is coated on the surface with ultrafines of an inorganic or metallic material. The coated particle is produced by introducing the particles of the inorganic or metallic material to be coated into a stream carrying the ultrafines of the inorganic or metallic material formed in a vapor phase and bringing the particles to be coated into contact with said ultrafines in a fluidized state. The coated particles are used for the production of a sintered product.

Abstract: A jet air flow crusher has a guide face formed by the inside surface of an outer wall in which a flat and almost ellipsoidal internal space is defined to guide an ellipsoidal gas phase flow powder grains; a crushing zone in which flowing powder grains are crushed provided on one side of the internal space in the direction of the ellipsoidal major axis; a classifying zone at which flowing powder grains are discharged provided on the other side of the internal space in the direction of the ellipsoidal major axis; a gas phase flow passage defined in the crushing zone by the inside surface of the outer wall and a partition wall; nozzles installed in the outer wall and the partition wall at several locations in the direction of the powder grain flow in the crushing zone to jet out air in a direction substantially corresponding to the powder grain flow for carrying and crushing the powder grains, and flow resisting means for limiting the gas phase flow carrying the powder grains, arranged at least at one location b

Abstract: In a powder classifier of the kind having a turbine-like horizontally rotating classifying rotor which is arranged to have air diametrically flow into radial passages and to cause the coarse powder portion of a powder material supplied to the inside of the radial passages to move to a circular passage encompassing the outer circumference of the rotor and the fine powder portion of the powder material to move diametrically toward the inside of the rotor, the circular passage has a discharge port formed in a part of the outer circumferential wall thereof. To the discharge port is connected a coarse powder discharge duct which approximately tangentially extends from the discharge port of the circular passage to a chute part arranged above a coarse powder recovering device; a powder return duct is connected to the chute part and extends approximately tangentially relative to the circular passage from the chute part to an opening provided in the outer circumferential wall of the circular passage.

Abstract: A powder disperser comprises a nozzle having a narrow discharge port for discharging a powder. A high speed air flow discharge port forms a narrow air port encompassing the outer circumference of the discharge port of the nozzle and is inwardly slanting at an acute angle relative to the discharge direction of a powder flow from the nozzle. A powder dispersing passage is narrowly formed on the downstream side of the nozzle in a circular tube like shape or in a radial shape along the outer wall surface continuing from the outer wall of the high speed air flow discharge port. The powder discharge passage is connected to the powder supply port of a classifier located downstream next to the disperser.

Abstract: A powder classifier having two stages of classification blades which are arranged to intersect the radial directions of the powder classifier.