Method for making amorphous particles using a uniform melt-state in a microwave generated plasma torch

• US 9,643,891 B2
• Filed: 01/15/2015
• Issued: 05/09/2017
• Est. Priority Date: 12/04/2012
• Status: Active Grant

• Current Assignee: 6K Incorporated
• Original Assignee: Amastan Technologies LLC
• Inventors: Hadidi, Kamal, Redjdal, Makhlouf
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US14/597,877
• Publication Number:
  US 20150126355A1
• Time in Patent Office: 845 Days
• Field of Search: 423600, 423625, 4235921, 423290, 423291, 423276, 423384, 423636, 423263
• CPC Class Codes: C01B 21/0605 Binary compounds of nitrogen with carbon
• CPC Class Codes: C01B 21/064 with boron
• CPC Class Codes: C01B 21/0646 Preparation by pyrolysis of boron and nitrogen containing compounds
• CPC Class Codes: C01B 21/0828 Carbonitrides or oxycarbonitrides of metals, boron or silicon
• CPC Class Codes: C01B 32/991 Boron carbide
• CPC Class Codes: C01F 17/218 Yttrium oxides or hydroxides
• CPC Class Codes: C01F 17/34 Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12
• CPC Class Codes: C01F 5/06 by thermal decomposition of magnesium compounds calcining magnesite or dolomite C04B2/10
• CPC Class Codes: C01F 7/162 Magnesium aluminates
• CPC Class Codes: C01F 7/30 Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
• CPC Class Codes: C01P 2002/02 Amorphous compounds
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/443 Nitrates or nitrites
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5481 Monomodal
• CPC Class Codes: C04B 35/44 based on aluminates
• CPC Class Codes: C04B 35/443 Magnesium aluminate spinel
• CPC Class Codes: C04B 35/505 : based on yttrium oxide
• CPC Class Codes: C04B 35/563 : based on boron carbide
• CPC Class Codes: C04B 35/583 : based on boron nitride
• CPC Class Codes: C04B 35/622 : Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
• CPC Class Codes: C04B 35/62665 : Flame, plasma or melting treatment
• CPC Class Codes: H05H 1/30 : using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/28 takes precedence

Abstract

Feed material comprising uniform solution precursor droplets is processed in a uniform melt state using microwave generated plasma. The plasma torch employed is capable of generating laminar gas flows and providing a uniform temperature profile within the plasma. Plasma exhaust products are quenched at high rates to yield amorphous products. Products of this process include spherical, highly porous and amorphous oxide ceramic particles such as magnesia-yttria (MgO—Y₂O₃). The present invention can also be used to produce amorphous non oxide ceramic particles comprised of Boron, Carbon, and Nitrogen which can be subsequently consolidated into super hard materials.

Claims

1. A method of producing amorphous powder particles comprising:

introducing a feed material as precursor droplets from a feed injection device into a microwave plasma torch;

entraining said feed material using laminar flow towards a microwave generated plasma;

exposing said feed material to the microwave generated plasma to form plasma exhaust gas;

quenching the plasma exhaust gas of said microwave generated plasma at a rate in the same order of magnitude of 10⁶ K/s to form amorphous powder particle products;

filtering the quenched plasma exhaust gas of said microwave generated plasma; and

extracting amorphous powder particle products from said filtered plasma exhaust gas.

2. The method of claim 1, wherein the precursor droplets are produced from a gas atomization process.

3. The method of claim 2, wherein the gas atomization process uses a pressurized tank.

4. The method of claim 2, wherein the precursor droplets have a diameter less than 100 microns.

5. The method of claim 1, wherein the precursor droplets have a diameter between 1 and 300 micrometers and a size distribution not exceeding 5%.

6. The method of claim 5, wherein the amorphous powder products are collected using ceramic or stainless steel filters with pore diameters not exceeding the diameter of the amorphous powder particle products.

7. The method of claim 1, wherein the feed material is comprised of homogenous precursor solutions of nitrates, acetates, alkoxides, or organometallics.

8. The method of claim 1, wherein the plasma torch is axisymmetric.

9. The method of claim 1, wherein the quenching step is done in air, or under inert gas conditions or under oxidizing conditions.

10. The method of claim 1, wherein the amorphous powder particle products are spherical, dense or porous.

11. The method of claim 1, wherein the amorphous powder particle products are metal oxides or metal oxide composites.

12. The method of claim 1, wherein the amorphous powder particle products are non-oxide compounds with the chemical formula C₃N₄, BN, B₄C, or BC₂N.

13. The method of claim 11, wherein the metal oxides or metal oxide composites are selected from the group consisting of:

MgO, Y₂O₃, Al₂O₃, MgO—

Y₂O₃, Y₃Al₅O₁₂, and MgAl₂O₄.