Nano-particles containing carbon and a ferromagnetic metal or alloy

Patent metadata

Field	Value
Publication number	US-11065688-B2
Application number	US-201715433637-A
Country	US
Kind code	B2
Filing date	Feb 15, 2017
Priority date	Apr 29, 2010
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

The invention relates to nano-particles comprising metallic ferromagnetic nanocrystals combined with either amorphous or graphitic carbon in which or on which chemical groups are present that can dissociate in aqueous solutions.
According to the invention there is provided nano-particles comprising metal particles of at least one ferromagnetic metal, which metal particles are at least in part encapsulated by graphitic carbon.
The nano-particles of the invention are prepared by impregnating carbon containing bodies with an aqueous solution of at least one ferromagnetic metal precursor, drying the impregnated bodies, followed by heating the impregnated bodies in an inert and substantially oxygen-free atmosphere, thereby reducing the metal compounds to the corresponding metal or metal alloy.

First claim

What is claimed is:

1. A process for the production of a nano-particle comprising a metal-carbon particle, wherein the metal-carbon particle comprises ferromagnetic metal particles at least partly encapsulated within graphitic carbon, wherein the process comprises:
impregnating a carbon containing body with an aqueous solution of a metal precursor;
drying the impregnated body; and
after drying the impregnated body, heating the impregnated body in a gas atmosphere at a temperature of above 700° C. to reduce a metal compound in the impregnated body to the ferromagnetic metal particles and to at least partly encapsulate the ferromagnetic metal particles within the graphitic carbon, wherein the gas atmosphere consists of inert gas.

2. The process according to claim 1 , wherein the ferromagnetic metal is iron.

3. The process according to claim 1 , wherein the metal precursor is one or more salts of one or more organic acids selected from the group consisting of citric acid, acetic acid, formic acid, hydroxyl acids and ammonium citrate.

4. The process according to claim 1 , wherein the carbon containing body is selected from the group consisting of microcrystalline cellulose, colloidal carbon, activated carbon bodies and mixtures thereof.

5. The process according to claim 1 , wherein the nano-particle comprises amorphous carbon, wherein the nano-particle is treated with an oxidizing agent, removing the amorphous carbon and producing carboxylic acid groups on the graphitic surfaces.

6. The process according to claim 1 , wherein the nano-particle is further treated in a flow comprising hydrogen and carbon containing molecules, wherein the nano-particle is completely encapsulated by graphitic carbon.

Assignees

• Basf Corp

Inventors

• Jenneskens Leonardus Wijnand
• Geus John Wilhelm
• Reesink Bernard Hendrik
• Berben Pieter Hildegardus
• Hoekstra Jacobus

Classifications

• B22F1/056

  Submicron particles having a size above 100 nm up to 300 nm · CPC title

• B22F1/16

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• B22F1/054

  Nanosized particles · CPC title

• B22F1/102

  Metallic powder coated with organic material · CPC title

• B22F9/26 Primary

  using gaseous reductors · CPC title