The invention relates to a method to form copper nanoparticles. The method comprises heating a solution comprising a copper precursor comprising at least one neat copper carboxylate in a concentration of at least 0.2 M, a stabilizer comprising an amine in a concentration equal or larger than the concentration of the copper precursor and optionally a solvent to a temperature T1 to form metallic copper. The solution is then heated to a temperature T2, with the temperature T2 being at least 10° C. higher than the temperature T1. The solution is heated from temperature T1 to temperature T2 with an average rate of at least 2 degrees per minute.

The invention further relates to copper nanoparticles obtainable by such method and to formulations comprising such nanoparticles.

A production method for a refined product of a metal nanoparticle-containing composition, including causing a metal nanoparticle-containing composition to pass in a liquid state from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure, and a production method for a refined product of a metal nanoparticle dispersion liquid, including causing a metal nanoparticle dispersion liquid to pass from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure.

A production method for a refined product of a metal nanoparticle-containing composition, including causing a metal nanoparticle-containing composition to pass in a liquid state from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure, and a production method for a refined product of a metal nanoparticle dispersion liquid, including causing a metal nanoparticle dispersion liquid to pass from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure.

An ejector of liquid material to form spherical particles includes a crucible for retaining liquid material, an orifice area defining at least one orifice, and an actuator responsive to a voltage signal for causing material to be ejected from the crucible through the orifice. A method comprises applying a voltage signal of a first type and a second type to the actuator, causing a material droplet of a first size and a second size to be ejected through the orifice. Alternately or in addition, the orifice area defines a first orifice having a first diameter and a second orifice having a second diameter different from the first diameter, whereby a signal causes a material droplet of a first size to be ejected through the first orifice and a material droplet of a second size to be ejected through the second orifice.

An ejector of liquid material to form spherical particles includes a crucible for retaining liquid material, an orifice area defining at least one orifice, and an actuator responsive to a voltage signal for causing material to be ejected from the crucible through the orifice. A method comprises applying a voltage signal of a first type and a second type to the actuator, causing a material droplet of a first size and a second size to be ejected through the orifice. Alternately or in addition, the orifice area defines a first orifice having a first diameter and a second orifice having a second diameter different from the first diameter, whereby a signal causes a material droplet of a first size to be ejected through the first orifice and a material droplet of a second size to be ejected through the second orifice.

Disclosed herein are systems and methods for synthesis of spheroidized metal or metal alloy powders using microwave plasma processing. In some embodiments, the metal or metal alloy may comprise a highly ductile, soft, and/or malleable metal or metal alloy such that machining of the metal or metal alloy is difficult or impossible. In some embodiments, a volatile material is dispersed within the metal or metal alloy feedstock to enable machining and pre-processing of the feedstock. In some embodiments, the dispersed volatile material alters the physical properties of the feedstock, such that the metal or metal alloy, which is difficult to machine due to high ductility, softness, and/or malleability, is easily machined in a pre-processing step. In some embodiments, the pre-processed feedstock, can be fed into a plasma processing apparatus. In some embodiments, the volatile material dispersed within the feedstock material may be vaporized upon exposure to the microwave plasma apparatus. In some embodiments, plasma processing of the pre-processed feedstock material may synthesize pure, spheroidized metal or metal alloy particles, with substantially no contamination of the volatile material ion the final product.

Disclosed herein are systems and methods for synthesis of spheroidized metal or metal alloy powders using microwave plasma processing. In some embodiments, the metal or metal alloy may comprise a highly ductile, soft, and/or malleable metal or metal alloy such that machining of the metal or metal alloy is difficult or impossible. In some embodiments, a volatile material is dispersed within the metal or metal alloy feedstock to enable machining and pre-processing of the feedstock. In some embodiments, the dispersed volatile material alters the physical properties of the feedstock, such that the metal or metal alloy, which is difficult to machine due to high ductility, softness, and/or malleability, is easily machined in a pre-processing step. In some embodiments, the pre-processed feedstock, can be fed into a plasma processing apparatus. In some embodiments, the volatile material dispersed within the feedstock material may be vaporized upon exposure to the microwave plasma apparatus. In some embodiments, plasma processing of the pre-processed feedstock material may synthesize pure, spheroidized metal or metal alloy particles, with substantially no contamination of the volatile material ion the final product.

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, γ-Fe and magnesium nitride.

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, γ-Fe and magnesium nitride.

A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.