Abstract: This method for manufacturing metal fine particles includes using an aqueous solution containing an amine having a reducing capacity and an ammonium salt having substantially no reducing capacity so as to reduce metal ions with said amine in a presence of said ammonium salt, thereby manufacturing rod-shaped metal fine particles. This metal fine particles are manufactured by this method for manufacturing metal fine particles, and have a major axis of 400 nm or less, a minor axis of 15 nm or less, and an aspect ratio of more than 1.

Abstract: A method of producing metal powder by reducing ions of a metal for precipitation by performance of a reducing agent in a liquid-phase reaction system, wherein the metal is precipitated as metal powder particles by being reduced under conditions in which the exchange-current density of an oxidation-reduction reaction between the metal ions and the reducing agent is 100 ?A/cm2 or less, the exchange-current density being determined by the mixed potential theory.

Abstract: A method of preparing metal nanoprisms having a unimodal size distribution and a predetermined thickness. The present method also allows control over nanoprism edge length.

Abstract: The invention provides a powder of fine particles of an alloy of platinum-family metal having a surface with a large amount of unevenness that is suitable as a catalyst metal. It is a powder of an alloy containing T and M in a composition ratio represented by the formula [TXM1?X], where T is one or two or more of the elements Fe, Co and Ni, M is one or two or more of the elements Pt, Pd and Ru, X represents a numerical value in the range 0.1-0.9, and wherein: its average grain size as measured under TEM observation (DTEM) is 50 nm or less, and under TEM observation, a plurality of protruding points is observed on the surface of the particles and indentations are observed between the protruding points, making it a fine powder of alloy particles with an uneven surface. This powder of fine alloy particles has a crystal structure with a face-centered cubic (fcc) structure, and its single crystallinity (DTEM)/(DX) is 1.50 or greater.

Abstract: Alloy particles of an alloy having a face-centered cubic structure comprise at least one selected from Fe and Co and at least one selected from Pt and Pd as principal components. The alloy particles have a TEM-measured average grain size (DTEM) of not more than 50 nm, and a single crystallinity (DTEM)/(DX) that is less than 1.50, where (DX) is X-ray crystallite size. These alloy particles can be advantageously manufactured by using the polyol process to synthesize the alloy particles in the presence of a complexing agent.

Abstract: Disclosed is a method for preparing metal nanoparticles, the method comprising the steps of: providing a solution of metal salt and a solution of a strong reducing agent with a standard reduction potential of ?0.23V or lower; and mixing the solutions by using a micro mixer without supplying additional heat energy from the exterior, while carrying out reduction of the metal. Metal nanoparticles obtained by the above method, and a micro mixer for preparing the metal nanoparticles are also disclosed. The method for preparing metal nanoparticles via the reduction of metal ions in a solution uses a strong reducing agent and a micro mixer. Therefore, it is possible to obtain metal nanoparticles having a particle size of 20 nm or more and a uniform shape and dimension without supplying additional heat energy from the exterior. Additionally, the method is amenable to a continuous process, and thus ensures cost-efficiency and stable product quality required for mass production.

Abstract: A synthetic method of fabricating highly crystalline and monodisperse nanoparticles of metals, multi-metallic alloys, monometallic oxides and multi-metallic oxides without a size selection process are disclosed. A typical synthetic method comprises the steps of, synthesis of a metal surfactant complex from the reaction of a metal precursor and a surfactant, high temperature thermal decomposition of the metal surfactant complex to produce monodisperse metal nanoparticles, and completing the formation of synthesized metal, metal alloy or metal oxide nanoparticles by adding a poor solvent followed by centrifuging. For obtaining highly crystalline monodisperse nanoparticles, additional steps are necessary as described in the invention. The resulting nanoparticles have excellent magnetic property for many applications.

Abstract: Dumbbell-shaped or flower-shaped nanoparticles and a process of forming the same, wherein the process comprises forming a mixture of a nanoparticle with a precursor in a first solvent, wherein the nanoparticle comprises a hydrophobic outer coating; heating the mixture; cooling the mixture to room temperature; modifying the hydrophobic outer coating into a hydrophilic outer coating; precipitating a solid product from the mixture, and dispersing the product in a second solvent. The nanoparticles comprise any of a semiconducting, magnetic, and noble metallic material, wherein the nanoparticles comprise a first portion comprising any of PbSe, PbS, CdSe, CdS, ZnS, Au, Ag, Pd, and Pt, and wherein the precursor comprises any of a cationic, neutral or particulate Au, Ag, Pd, Pt, or transition metal (Fe, Co, Ni) precursors of Fe(CO)5, Co(CO)8, Ni(CO)4 or their analogues. The first and second solvents comprise any of alkanes, arenes, ethers, nitrites, ketones, and chlorinated hydrocarbons.

Abstract: An object of the present invention is to provide a silver powder which is an unprecedentedly fine particulate silver powder and has a dispersibility more approximate to monodispersibility resulting less aggregation. To achieve the above object, a fine particulate silver powder having unprecedented powder properties in which: a. the average particle diameter DIA of the primary particles obtained by image analysis of a scanning electron micrograph is 0.6 ?m or less; b. the crystallite diameter is 10 nm or less; and c. the sintering starting temperature is 240° C.

Abstract: The present teachings are directed toward single metal and alloy nanoparticles and synthesis methods for preparing single metal and alloy nanoparticles.

Abstract: This invention relates to a composition of matter comprising associated predominantly silver nanoparticles, and a method of making the nanoparticles. It further relates to articles comprising the nanoparticles.

Abstract: A method of producing (1) metal particles or (2) metal fine-particles, which contains: jetting out two solutions of (1) a metal salt solution and a reducing agent solution, or (2) a metal ion-containing solution and a hydroxide ion-containing solution, from respective nozzles to a mixing chamber, to give a mixed reaction solution; and discharging the mixed reaction solution from a discharging port having a diameter smaller than a diameter of the mixing chamber, wherein one of the two solutions is made into straightly-going flow, which is jetted from a nozzle having a diameter smaller than the diameter of the mixing chamber to the mixing chamber, and the other solution is jetted out, as flow substantially orthogonal to the straightly-going flow, to a position before a position where eddy viscosity generated by the straightly-going flow would be maximum.

Abstract: A method for making Nano-scale lead-free solder includes the following steps of: forming a mixture solution Sn-Ag or Sn-Ag-Cu; making NaBH4, NaOH and alkyl C12H25OSO3Na to a reducing dispersing solution; producing reactant Sn-Ag or Sn-Ag-Cu by means of the oxidation reduction method; and adding 95% ethanol to be mixed, and cleaning the reactant by using a supersonic vibrator for removing boron (B) and sulfur (S) atom which adhere to the reactant, thereby producing the Nano-scale (0.1˜100 nm) lead-free solder Sn-3.5Ag or Sn-3.5Ag-xCu (x=0.2˜1.0).

Abstract: A process comprising: reacting a silver compound with a reducing agent comprising a hydrazine compound in the presence of a thermally removable stabilizer in a reaction mixture comprising the silver compound, the reducing agent, the stabilizer, and an optional solvent, to form a plurality of silver-containing nanoparticles with molecules of the stabilizer on the surface of the silver-containing nanoparticles.

Abstract: The present invention is directed to methods for forming nanosized metal particles. Preferably, nanosized noble metal particles are formed. According to the methods of the invention, a product containing nanosized metal particles in a solvent are formed. Additionally, processing to remove undesirable byproducts created or used during the fabrication process are not necessary.

Abstract: Gold nanoparticles having a particle size of 4-15 nM are synthesized by the reduction of hydrogen tetrachloroaurate (III) trihydrate using a suitable reducing agent such as sodium citrate in the presence of unmodified ?, ? or ?-cyclodextrin. The particle size is dependent upon the type and concentration of cyclodextrin and the reducing agent concentration. Gold nanoparticles having a particle size of 2-4 nM are produced by the reduction of hydrogen tetrachloroaurate (III) trihydrate using sodium borohydride in the presence of cyclodextrins.

Abstract: A method for producing a copper/palladium colloid catalyst useful for Suzuki couplings.

Abstract: A method for forming a supported metal-containing powder. The method comprises forming a dispersion of a particulate support in a solution, which comprises a solvent and a dissolved metal. Heat is removed from the dispersion to precipitate the dissolved metal from the solution onto the particulate support. Preferably, enough heat is removed to freeze the solution. Also, the heat is removed is preferably removed from the dispersion by contacting a container containing the dispersion with a cryogenic liquid. After precipitating the dissolved metal onto the particulate support, the particulate support is separated from the solution, preferably by freeze-drying, to yield the supported metal-containing powder, which comprises the particulate support and a precipitated metal thereon.

Abstract: Electrocatalyst powders and methods for producing electrocatalyst powders, such as carbon composite electrocatalyst powders. The powders have a well-controlled microstructure and morphology. The method includes forming the particles from an aerosol of precursors by heating the aerosol to a relatively low temperature, such as not greater than about 400° C.

Abstract: A method of producing a nanoparticle, the method comprising: a reducing step of adding an reverse micelle solution (II) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous metal salt solution to an reverse micelle solution (I) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous reducing agent solution, to carry out a reducing reaction; and a maturing step of raising the temperature of the reduced mixture to mature the reduced mixture is provided. A method of producing a plural type alloy nanoparticle, the method comprising producing a nanoparticle made of a plural type alloy through a reducing step of mixing one or more reverse micelle solutions (I) containing a metal salt with an reverse micelle solution (II) containing a reducing agent to carry out reducing treatment and a maturing step of carrying out maturing treatment is also provided.

Abstract: A process for preparing a pure PGM (platinum group metal) from a material containing a plurality of PGM compounds, wherein the PGM is selected from the group consisting of Pt, Pd, Os, Ir, Ru, Rh and Re, and the process includes initially forming the PGM in activated form by reduction of PGM ions in aqueous solution at pH 6–8 by a reducing agent, preferably, hydrogen.

Abstract: An electrochemical displacement-deposition method for making composite metal powders is described. The method is carried out by combining tungsten or molybdenum metal particles with particles of silver oxide or copper oxide in an aqueous hydroxide solution. Heat is applied to the solution to cause the oxide particles to convert to silver or copper metal particles which are substantially adhered to the refractory metal particles. Unlike conventional methods, it is not necessary to heat the oxide powders to a very high temperature in a reducing atmosphere in order to form the composite metal powder.

Abstract: A new low temperature method of reducing metallic salts, both inorganic and organic to metallic nanoparticles has been discovered. The reduction reaction is carried out in low boiling point monoalkylethers of ethylene glycol and mixtures of this solvent with alkane diols. Metallic nanoparticles are produced with size range of 1–100 nm.

Abstract: Metal nanoparticles are formed by heating or refluxing a mixture of a metal salt, such as a metal acetate, and a passivating solvent, such as a glycol ether, at a temperature above the melting point of the metal salt for an effective amount of time.

Abstract: Metal nanoparticles containing two or more metals are formed by heating or refluxing a mixture of two or more metal salts, such as a metal acetates, and a passivating solvent, such as a glycol ether, at a temperature above the melting point of the metal salts for an effective amount of time.

Abstract: A process for producing metallic titanium includes forming metallic titanium fine particles by supplying liquid or mist titanium tetrachloride from above the surface of a reaction bath liquid containing fused magnesium and fused magnesium chloride in a reaction vessel to effect a reaction, wherein a circulating flow perpendicular to the bath surface of the reaction bath liquid is generated or extended just under the bath surface by imparting a stirring force to the reaction bath liquid so as to generate or increase an upward flow rate of the reaction bath liquid in at least part of the region at a depth of more than 100 mm below the bath surface.

Abstract: A method for providing an anhydrous route for the synthesis of amine capped coinage-metal (copper, silver, and gold) nanoparticles (NPs) using the coinage-metal mesityl (mesityl=C6H2(CH3)3-2,4,6) derivatives. In this method, a solution of (Cu(C6H2(CH3)3)5, (Ag(C6H2(CH3)3)4, or (Au(C6H2(CH3)3)5 is dissolved in a coordinating solvent, such as a primary, secondary, or tertiary amine; primary, secondary, or tertiary phosphine, or alkyl thiol, to produce a mesityl precursor solution. This solution is subsequently injected into an organic solvent that is heated to a temperature greater than approximately 100° C. After washing with an organic solvent, such as an alcohol (including methanol, ethanol, propanol, and higher molecular-weight alcohols), oxide free coinage NP are prepared that could be extracted with a solvent, such as an aromatic solvent (including, for example, toluene, benzene, and pyridine) or an alkane (including, for example, pentane, hexane, and heptane).

Abstract: A method for the production of a robust, chemically stable, crystalline, passivated nanoparticle and composition containing the same, that emit light with high efficiencies and size-tunable and excitation energy tunable color. The methods include the thermal degradation of a precursor molecule in the presence of a capping agent at high temperature and elevated pressure. A particular composition prepared by the methods is a passivated silicon nanoparticle composition displaying discrete optical transitions.

Abstract: A method for purifying a suspension containing colloid-seeded nanoparticles and excess colloids is provided that includes adding to the suspension a filter aid comprising a salt. The method further includes filtering the suspension with a filter of a pore size intermediate between the average colloid-seeded nanoparticle size and the average excess colloid size, so as to form a retentate that includes the majority of the colloid-seeded nanoparticles and a filtrate that includes the majority of the excess colloids. Still further, the method includes collecting the retentate. The method may be incorporated into a method of making metallized nanoparticles, such as nanoshells, by reduction of metal ions onto the purified colloid-seed nanoparticles so as to form the metallized nanoparticles.

Abstract: Methods for making metal-based nanoparticles and inks are disclosed. In accordance with the method of the present invention, molecular metal precursors are reduced in the presence of a reaction medium to form the nanoparticles. The molecular metal precursors are preferably reduced by heating the metal precursor in the medium, by adding a reducing agent, such an aldehyde or a combination thereof. Metal precursor are preferably metal oxides, transition metal complexes or combination thereof. The method of the present invention is used to make high yield nanoparticles with a range of particle size distributions. Nanoparticle formed by the present invention include mixtures of nanoparticle, alloy nanoparticles, metal core shell nanoparticles or nanoparticle comprising a single metal species.

Abstract: The present invention relates to an improved process for the production of neodymium-iron-boron permanent magnet alloy powder. The neodymium-iron-boron alloy prepared by the process of the present invention can be processed further to get anisotropic permanent magnets, bonded as well as sintered.

Abstract: Gold powders and methods for producing gold powders. The powders preferably have a small particle size, narrow size distribution and a spherical morphology. The method includes forming the particles by a spray pyrolysis technique. The invention also includes novel devices and products formed from the gold powders.

Abstract: The invention provides platinum or platinum alloy powders for use in fuel cells and for chemical reactions. The powders are characterized by a high surface area and, at the same time, low chlorine contents. The powders are prepared by forming a melt which contains, as starting substances, a low melting mixture of alkali metal nitrates, a chlorine-free platinum compound and optionally chlorine-free compounds of alloying elements, the melt is then heated to a reaction temperature at which the platinum compound and the compounds of alloying elements thermally decompose to give oxides, the melt is then cooled and dissolved in water and the oxides or mixed oxides formed are converted into platinum or platinum alloy powders by subsequent reduction. Binary or ternary eutectic mixtures from the LiNO3—KNO3—NaNO3 system are suitable as a low melting mixture of nitrates of the alkali metals. Hexahydroxoplatinic-(IV)-acid is preferably used as a chlorine-free platinum compound.

Abstract: Disclosed is a method for producing core-shell type metallic nanoparticles involving (i) providing a dispersion of a first metal as nanoparticles in an appropriate organic solvent; (ii) providing a solution of a metallic precursor containing a second metal in an appropriate organic solvent, in which the second metal has a reduction potential higher than that of the first metal; and (iii) combining the dispersion from (i) and the solution from (ii) together to carry out the transmetalation reaction of the first and second metals, thereby forming core-shell type metallic nanoparticles.

Abstract: An article of a base metal alloyed with an alloying element is prepared by mixing a chemically reducible nonmetallic base-metal precursor compound of a base metal and a chemically reducible nonmetallic alloying-element precursor compound of an alloying element to form a compound mixture. The alloying element is preferably thermophysically melt incompatible with the base metal. The method further includes chemically reducing the compound mixture to a metallic alloy, without melting the metallic alloy, and thereafter consolidating the metallic alloy to produce a consolidated metallic article, without melting the metallic alloy and without melting the consolidated metallic article.

Abstract: Ultrafine composite metal particles comprising a surfactant sheath and an organic compound sheath that surround a metal core in which metal atoms obtained by reduction precipitation from an organic metal compound have agglomerated, the particle diameter being 1 to 100 nm. The ultrafine composite metal particle may comprise a surfactant sheath that surrounds a metal core in which metal atoms obtained by reduction precipitation from an inorganic metal compound have agglomerated. The ultrafine composite metal particles are obtained by forming an ultrafine particle precursor by producing a colloidal solution of an organic metal compound or an inorganic metal compound in a nonaqueous solvent using a surfactant, and by reducing the ultrafine particle precursor by adding a reducing agent to this colloidal solution, thus forming ultrafine composite metal particles with a diameter of 1 to 100 nm and having at least a surfactant sheath around a metal cored.

Abstract: 1. A niobium powder for capacitors, wherein the chromium content is 50 ppm by mass or less, granulated product and sintered body thereof, and producing method of those; 2. a capacitor constructed by one part electrode formed of the niobium sintered body, another part electrode and a dielectric material interposed between two electrodes, and its producing method; and 3. an electronic circuit and electronic device using the capacitor. A capacitor having good voltage resistance properties can be manufactured by using the niobium sintered body for capacitors of the present invention, wherein the chromium content is 50 ppm by mass or less.

Abstract: The production and selection of precursor mixtures used to produce fine powders and methods for making fine powders using the selected precursor. The precursor mixture comprises at least one metal containing precursor, the metal containing precursor has an average molecular weight of less than 2000 grams per unit mol of the metal, the metal containing precursor has a normal boiling point greater than 350K, and the viscosity of the precursor mixture is between 0.1 to 250 cP. The precursor mixture is processed under conditions that produce a fine powder from the precursor mixture. Fine powders produced are of size less than 100 microns, preferably less than 10 micron, more preferably less than 1 micron, and most preferably less than 100 nanometers.

Abstract: Metal coated powders are produced by suspending a precursor metal salt and the powder to be coated in a glycol. This mixture is heated, and the metal salt is reduced and the metal precipitates as a coating onto the powder.

Abstract: A method for making nanoparticles via metal salt reduction comprises, first, mixing metal salts in a solvent. Second, a reducing agent is added to the solvent at a temperature in the range of 100° C. to 350° C. Third, the nanoparticles dispersion is stabilized. Fourth, the nanoparticles are precipitated from the nanoparticle dispersion. Finally, the nanoparticles are re-dispersed into the solvent. The metal salt comprises a combination of FeCl2, FeCl3, Fe(OOCR)2, Fe(RCOCHCOR)3, CoCl2, Co(OOCR)2, Co(RCOCHCOR)2, and one of Pt(RCOCHCOR)2, PtCl2. The reducing agent comprises one of MBR3H, MH, M naphthalides, and polyalcohol; wherein R comprises one of H and an alkyl group, wherein M comprises one of Li, Na, and K. Long chain alkyl diols, and alkyl alcohol, can be used as a co-surfactant or a co-reducing agent to facilitate nanoparticle growth and separation.

Abstract: The present invention relates to the preparation of nanoparticles of silver (Ag) and silver alloyed with other elements such as platinum (Pt), palladium (Pd), gold (Au), aluminum (Al), cadmium (Cd) and sulfur (S) in surfactant solutions. The surfactant molecules have the intrinsic property to adsorb into the interface, which are formed between two different phases. Thus, the surfactant molecules would adsorb into the surface of nuclei in solution. The adsorbed surfactant molecules from the solution prevent the coalescence of particles and control the rate of particle growth. By choosing the proper kind and/or concentration of surfactants, the size of particles formed in solution can be controlled in nm scale.

Abstract: A process for forming metal nanocrystals involves complexing a metal ion and an organic ligand in a solvent and introducing a reducing agent to reduce a plurality of metal ions to form the metal nanocrystals associated with the organic ligand. The nanocrystals are optionally doped or alloyed with other metals.

Abstract: The nickel powder is characterized in that the rate of the nickel particles whose particle size is not less than 1.2 time the average particle size as determined by the observation with an SEM is not more than 5% of the total number of nickel particles and that the rate of nickel particles whose particle size is not more than 0.8 time the average particle size is not more than 5% of the total number of nickel particles. The nickel powder is produced by bringing a slurry, containing nickel hydroxide, which is prepared by adding an aqueous solution of a nickel salt to an aqueous solution of an alkali metal hydroxide, into contact with a hydrazine reducing agent under the temperature conditions of not less than 55° C. to reduce the nickel hydroxide.

Abstract: A process for preparing metal nanoparticles, comprising reacting suitable metal salts and anionic surfactant containing an anionic group of carboxylic group (COO−), sulfate group (SO42−) or sulfonate group (SO32−) as reducing agent in water under reflux at a temperature of 50-140° C., such that under the reducing power of said anionic surfactant itself, the metal salts can be effectively reduced into metal nanoparticles having a uniform particle size and that the reaction will be not too fast, no large microparticle will be formed, the yield will not be lowered, and the nanoparticle thus prepared can be dispersed stably in polar and non-polar solvent.

Abstract: A process is described for the production of metal powder and alloy powders containing at least one of the metals iron, copper, tin, cobalt or nickel, by mixing aqueous metal salt solutions with an aqueous carboxylic acid solution, separating the precipitation product from the mother liquor and reducing the precipitation product to the metal.

Abstract: This invention aims at providing a method of obtaining fine alloy powders, which are extremely small in particle size, high in purity, and uniform in composition, providing fine alloy powders obtained by this method, and providing molding materials, slurries, and electromagnetic shielding materials, which use these fine alloy powders. This invention provides a fine alloy powder production method, which is characterized in that after performing the process of mixing at least a trivalent titanium compound and a complexing agent, which binds with the trivalent titanium ion, in an aqueous solution containing two or more types of metal ion, the two or more types of metal are made to deposit simultaneously.

Abstract: Tungsten carbide is formed from a tungsten material which is preferably tungsten carbide scrap. If scrap material is used, this is oxidized and acid leached to remove impurities and any binder material. This is then dissolved in a solution of sodium hydroxide and spray dried to form a precursor compound. A carbon compound such as citric acid can be added to the solution prior to spray drying to provide a carbon source for the tungsten carbide. The powder formed from the spray dried solution is calcined and carburized to form tungsten carbide.

Abstract: A continuous method for generating substantially submicron sized metal particles in a liquid dispersion of known viscosity. Metal carbonyl gas and an inert carrier gas, with an optional dilutant gas, are introduced into a heated liquid bath wherein the metal carbonyl decomposes into submicron sized pure metal particles. The particles are suspended in the liquid. The liquid is processed to form slurries and pastes.

Abstract: Provided is a method for manufacturing a metal powder by providing a reducing solution by dispersing caustic alkali, and hydrazine and/or hydrazine hydrate into a solvent; providing a metal salt solution comprising a salt of electroconductive metal, a rare earth metal salt and a solvent; and mixing the reducing solution with the metal salt solution to form a metal powder by depositing a hydroxide derived from the rare earth metal salt and by reducing the salt of electroconductive metal. With this metal powder manufacturing method, the sintering of the metal powder is restricted at a low temperature, the sintering initiation temperature is shifted to a higher level, and rapid sintering shrinkage is restricted, while ceramic grain growth is not accelerated.

Abstract: A process is described for the preparation of powder mixtures or composite powders from at least one first type of powder from the group consisting of high-melting metals, hard materials and ceramic powders and at least one second type of powder from the group consisting of binder metals, binder-metal mixed crystals and binder-metal alloys, where the second type of powder is formed from precursor compounds in the form of water-soluble salts in an aqueous suspension of the first type of powder by precipitation as oxalate, removal of the mother liquor and reduction to the metal.