While a water reaction system containing silver ions is irradiated with ultrasonic waves to cause cavitation therein, a reducing agent containing solution, which contains an aldehyde as a reducing agent, is mixed with the water reaction system to deposit silver particles, the solid-liquid separation of which is carried out, and thereafter, the separated silver particles are washed and dried to produce a spherical silver powder which has a closed cavity in each particle thereof.

The present invention relates to hollow nanoparticles having inside their cavity a metal core constituted by metal seeds agglomerated with a cationic polyelectrolyte, useful in medicine as well as in the bio-imaging and/or radio-therapeutic or chemo-therapeutic techniques and also in the industry as starting materials for preparing catalysts or metamaterials in non-linear optical processes.

The present invention relates to hollow nanoparticles having inside their cavity a metal core constituted by metal seeds agglomerated with a cationic polyelectrolyte, useful in medicine as well as in the bio-imaging and/or radio-therapeutic or chemo-therapeutic techniques and also in the industry as starting materials for preparing catalysts or metamaterials in non-linear optical processes.

Provided are methods for making hollow gold nanospheres.

Disclosed are interfacially modified particulate and polymer composite material for use in injection molding processes, such as metal injection molding and additive process such as 3D printing. The composite material is uniquely adapted for powder metallurgy processes. Improved products are provided under process conditions through surface modified powders that are produced by extrusion, injection molding, additive processes such as 3D printing, Press and Sinter, or rapid prototyping.

Disclosed are interfacially modified particulate and polymer composite material for use in injection molding processes, such as metal injection molding and additive process such as 3D printing. The composite material is uniquely adapted for powder metallurgy processes. Improved products are provided under process conditions through surface modified powders that are produced by extrusion, injection molding, additive processes such as 3D printing, Press and Sinter, or rapid prototyping.

A method of preparing hollow metal or metal oxide nano- or microspheres is provided. The method comprises providing a suspension comprising monodispersed polydopamine nano- or microspheres, forming a layer of metal or metal oxide on the monodispersed polydopamine nano- or microspheres, and adding an alkaline solution to the suspension to dissolve the polydopamine thereby forming the hollow metal or metal oxide nano- or microspheres.

A process for the synthesis of nanostructured metallic hollow spherical particles, in which the metal is deposited onto sacrificial masks formed in a polymeric colloidal solution by the electroless autocatalytic deposition method. Deposition releases only gaseous products (N.sub.2 and H.sub.2) during the oxidation thereof, which evolve without leaving contaminants in the deposit. The particulate material includes nanostructured metallic hollow spherical particles with average diameter ranging from 100 nm to 5 m and low density with respect to the massic metal. A process for compacting and sintering a green test specimen are also described.

Provided in the present disclosure are metal particles and a preparation method therefor, the preparation method for the metal particles comprising the following step: in the presence of a first dispersing agent and a second dispersing agent, subjecting an oxidizing agent containing a metal source and a reducing agent to a redox reaction, so as to obtain the metal particles, wherein the first dispersing agent comprises a first organic solvent having a low molecular weight and at least one nanoparticle, and the second dispersing agent comprises a second organic solvent having a high molecular weight. The metal particles of the present disclosure have the advantages of a high shrinkage ratio, a high specific surface area, high sphericity, etc.; and the preparation method is simple and efficient.

Provided in the present disclosure are metal particles and a preparation method therefor, the preparation method for the metal particles comprising the following step: in the presence of a first dispersing agent and a second dispersing agent, subjecting an oxidizing agent containing a metal source and a reducing agent to a redox reaction, so as to obtain the metal particles, wherein the first dispersing agent comprises a first organic solvent having a low molecular weight and at least one nanoparticle, and the second dispersing agent comprises a second organic solvent having a high molecular weight. The metal particles of the present disclosure have the advantages of a high shrinkage ratio, a high specific surface area, high sphericity, etc.; and the preparation method is simple and efficient.