The present disclosure is directed to methods of preparing substantially spherical metallic alloyed particles, having micron and sub-micron (i.e., nanometer)-scaled dimensions, and the powders so prepared, as well as articles derived from these powders. In particular embodiments, these metallic alloyed particles, comprising rare earth metals, can be prepared in sizes as small 80 nm in diameter with size variances as low as 2-5%.

A metal powder production apparatus includes a molten metal supply section which supplies a molten metal, a cylindrical body which includes an upper part placed on a lower side of the molten metal supply section and a lower part provided on a lower side of the upper part, a fluid jet section which jets a gas (fluid) toward the molten metal, and a cooling liquid outflow section which allows a cooling liquid to flow out along the inner circumferential surface of the upper part. In the metal powder production apparatus, an angle formed by the axial line of the upper part of the cylindrical body and the vertical line is 0 or more and 20 or less, and an angle formed by the axial line of the lower part of the cylindrical body and the vertical line is 0 or more and 20 or less.

A water-atomized metal powder is produced by dividing a molten metal stream into a metal powder by making injection water having a liquid temperature of 10 C. or less and an injection pressure of 5 MPa or more impinge on the molten metal stream and cooling the metal powder. Cooling with injection water having a liquid temperature of 10 C. or less and an injection pressure of 5 MPa or more enables can be performed not in the film boiling region but in the transition boiling region from the beginning of cooling. A gas-atomized metal powder may also be produced by dividing a molten metal stream into a metal powder by making an inert gas impinge on the molten metal stream and cooling the metal powder with injection water having a liquid temperature of 10 C. or less and an injection pressure of 5 MPa or more.

Embodiments of the invention generally include apparatus and methods for depositing nanowires in a predetermined pattern during an electrospinning process. An apparatus includes a nozzle for containing and ejecting a deposition material, and a voltage source coupled to the nozzle to eject the deposition material. One or more electric field shaping devices are positioned to shape the electric field adjacent to a substrate to control the trajectory of the ejected deposition material. The electric field shaping device converges an electric field at a point near the surface of the substrate to accurately deposit the deposition material on the substrate in a predetermined pattern. The methods include applying a voltage to a nozzle to eject an electrically-charged deposition material towards a substrate, and shaping one or more electric fields to control the trajectory of the electrically-charged deposition material. The deposition material is then deposited on the substrate in a predetermined pattern.

A process for the production of steel powders including the steps of: providing molten iron from a blast furnace, refining the molten iron in a converter to form molten steel, refining the molten steel in a vacuum arc degasser to obtain a refined molten steel comprising from 20 to less than 600 ppm C, from 15 to less than 120 ppm S, up to 125 ppm P, up to 80 ppm N and up to 30 ppm O, pouring in a plurality of induction furnaces, adding at least one ferroalloy, pouring the molten steel of each induction furnace in a dedicated reservoir connected to at least one gas atomizer, feeding the at least one gas atomizer of each reservoir in molten steel from each reservoir under pressure and gas atomizing the molten steel to form the steel powder at the desired composition.

A method for producing material powder, comprising providing material and an atomization gas charged with an atomization gas pressure by means of an atomization gas compressor to an atomization device, melting the material and pulverizing the molten material into material powder by means of charging the molten material with the atomization gas using the atomization device, introducing the material powder from the atomization device into a pressurized container and providing a conveyor gas charged with a conveyer gas pressure by means of a conveyer gas compressor to the pressurized container, wherein the conveyor gas pressure is higher than the atmospheric pressure and lower than the atomization gas pressure, as well as a device for carrying out the method.

A process for manufacturing metal powders including: i) feeding an atomization chamber of a gas atomizer with molten metal, (ii) atomizing the molten metal by injection of gas so as to form metal particles, (iii) transferring the metal particles from the atomization chamber to a cooling chamber of the gas atomizer, (iv) cooling the metal particles in the cooling chamber by injecting gas from the bottom of the cooling chamber so as to form a bubbling fluidized bed of metal particles. A gas atomizer thereof is also provided.

A device for producing metal powder. This includes a melting chamber, a downstream atomization tower, and a nozzle assembly for atomizing a melt jet. The device further includes an induction coil disposed within the melting chamber and operated at a melting frequency f.sub.melt, the induction coil is adapted to locally melt a material rod at least section-wise received therein, to produce the melt jet to be atomized, and a separate intermediate coil disposed within the melting chamber and operated at a base frequency f.sub.base, wherein said intermediate coil is disposed downstream of the induction coil and aligned coaxially with the induction coil. The intermediate coil is configured to superheat the melt jet in a region between the induction coil and the nozzle assembly. The following applies to a frequency ratio F.sub.BS of the base frequency f.sub.base to the melting frequency f.sub.melt, 1?F.sub.BS=f.sub.base/f.sub.melt?500.

A reservoir of molten metal atomizer including i) a tundish including a) a bottom and a side substantially delimiting a central cavity whose bottom comprises a central portion and a periphery, b) at least one discharging zone in the form of a top-opened recess in the side of the tundish and including a bottom positioned at most at the level of the periphery of the bottom of the central cavity, a discharging opening in the bottom and a shut-off device for the discharging opening, ii) a bell whose lip is positioned towards the bottom of the tundish, the bell being substantially centered on the tundish and extending above at least 50% of the bottom of the tundish, the bell including in its upper section a gas injector. The process thereof is also provided.

An arc reactor and a process for the production of nanoparticles are disclosed. The reactor has a crucible in a gas-tight housing having a carrier gas inlet and a spaced-apart carrier gas outlet. The carrier gas inlet is directed to the side of the crucible opposite the crucible opening. The inlet can be disposed below the crucible and directed to the side of the crucible opposite the crucible opening. The carrier gas outlet is disposed above the crucible and exits the housing above the crucible. The carrier gas outlet is formed by a hood disposed at a distance above the crucible, which is separated from the crucible and formed by an exhaust pipe that connects the hood to the carrier gas outlet of the housing. The reactor housing has at least one inlet for cooling gas. This can be directed at an interstice formed between the crucible and the hood.