# US 8,147,793 B2 · Process for the manufacture of nano-sized powders

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- Number: US 8,147,793 B2
- Document ID: US8147793B2
- Status: Granted
- Kind: B2
- Application number: 12/515,476
- Filed: 2007-10-18
- Published: 2009-12-10
- Granted: 2012-04-03
- Earliest claimed: 2006-12-01
- Assignees: Umicore AG & Co. KG
- Inventors: Stijn Put; Yves Van Rompaey; Sylvain Van Den Rul
- Web page: https://patentgrep.com/patent/US8147793B2

## CPC

- B01J 19/088: {giving rise to electric discharges (for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00)}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B01J 2219/00157: by means of a burner
- B01J 2219/0886: Gas-solid
- B01J 2219/0898: Hot plasma
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2002/76: by a space-group or by other symmetry indications
- C01P 2004/03: obtained by SEM
- C01P 2004/64: Nanometer sized, i.e. from 1-100 nanometer
- C01P 2006/12: Surface area
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

Nano-sized metal-bearing powders and doped-powders are synthesized by means of a process whereby a non-volatile metal-bearing precursor powder or powder mixture is dispersed in a hot gas stream at relatively low temperatures. A first volatile reactant is added, converting the metal in the precursor into a volatile metal compound. Subsequently a second volatile reactant is injected into the gas stream, converting the volatile metal compound into a solid, which condenses as a nano-sized metal-bearing powder upon quenching. Finally, the vapour/metal-bearing powder mixture is separated from the gas stream.

## Claims

### Claim 1

A process for the production of a nano-sized metal-bearing powder comprising:
(a) providing a hot gas stream at a temperature of 1000 K to 3000 K, wherein
a solid metal-bearing precursor compound is dispersed; and
a first volatile reactant is introduced,
whereby a gaseous metal intermediate compound is formed, said compound being volatile at a temperature lower than the volatilization temperature of the precursor;
(b) introducing a second volatile reactant into the gas stream whereby the gaseous metal intermediate compound is converted into a nano-sized metal-bearing powder; and
(c) separating the nano-sized metal-bearing powder from the gas stream.

### Claim 2 (depends on 1)

The process of claim 1, wherein the solid metal-bearing precursor is non-volatile at the temperature of the hot gas stream.

### Claim 3 (depends on 1)

The process of claim 1, wherein between the step of introducing the second volatile reactant and separating the nano-sized metal-bearing powder, the gas stream is quenched.

### Claim 4 (depends on 1)

The process of claim 1, wherein during the step of introducing the second volatile reactant, the gas stream is quenched.

### Claim 5 (depends on 1)

The process of claim 1, wherein the nano-sized metal-bearing powder that is produced comprises a nano-sized, doped metal-bearing powder and wherein the solid metal-bearing precursor compound comprises a solid metal-bearing precursor powder mixture containing at least two metals.

### Claim 6 (depends on 1)

The process of claim 1, wherein the nano-sized metal-bearing powder that is produced comprises a nano-sized, doped metal-bearing powder and wherein the solid metal-bearing precursor compound comprises a solid metal-bearing precursor powder that is dispersed in a second metal-bearing liquid or gaseous precursor.

### Claim 7 (depends on 1)

The process of claim 1, wherein the hot gas stream is provided by a gas burner, a hydrogen burner, an RF plasma, or a DC arc plasma.

### Claim 8 (depends on 1)

The process of claim 1, wherein the solid precursor comprises one or more of ZnO, GeO2, In2O3, indium-tin-oxide, MnO2, Mn2O3 or Al2O3.

### Claim 9 (depends on 1)

The process of claim 1, wherein the first volatile reactant comprises one or more of hydrogen, nitrogen, chlorine, CO, or a volatile hydrocarbon.

### Claim 10 (depends on 9)

The process of claim 9, wherein the volatile hydrocarbon is methane or ethane.

### Claim 11 (depends on 1)

The process of claim 1, wherein the second volatile reactant comprises one or more of oxygen or nitrogen.

### Claim 12 (depends on 11)

The process of claim 11, wherein the second volatile reactant is air.

### Claim 13 (depends on 1)

The process of claim 1, wherein the solid precursor comprises a micron-sized or sub-micron-sized ZnO powder, the first volatile reactant is methane, and the second volatile reactant is air.

### Claim 14 (depends on 13)

The process of claim 13, wherein the second volatile reactant quenches the hot gas stream to a temperature below 250° C.

### Claim 15 (depends on 13)

The process of claim 13, wherein the solid precursor is a mixture of ZnO and one or more of Al2O3, Al, or MnCl3 powder.