Very high purity fine powders and methods to produce such powders

• US 6,569,397 B1
• Filed: 08/15/2000
• Issued: 05/27/2003
• Est. Priority Date: 02/15/2000
• Status: Expired due to Term

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: Tapesh Yadav
• Inventors: Yadav, Tapesh, Pfaffenbach, Karl
• Primary Examiner(s): Hendrickson, Stuart L.
• Application Number:
  US09/638,977
• Time in Patent Office: 1,015 Days
• Field of Search: 423/440, 423/439, 423/345
• US Class Current: 423/345
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 2219/0886 Gas-solid
• CPC Class Codes: B01J 2219/0894 Processes carried out in the presence of a plasma
• CPC Class Codes: B22F 2202/13 Use of plasma
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 9/12 starting from gaseous material
• CPC Class Codes: B22F 9/14 using electric discharge
• CPC Class Codes: B22F 9/30 with decomposition of metal compounds, e.g. by pyrolysis
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/14 Methods for preparing oxides or hydroxides in general particular individual oxides or hydroxides, see the relevant groups of subclasses C01B - C01G or C25B, according to the element combined with the oxygen or hydroxy group
• CPC Class Codes: C01B 13/20 by oxidation of elements in the gaseous state; by oxidation or hydrolysis of compounds in the gaseous state
• CPC Class Codes: C01B 21/06 Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boronazides C01B21/08
• CPC Class Codes: C01B 21/0828 Carbonitrides or oxycarbonitrides of metals, boron or silicon
• CPC Class Codes: C01B 32/956 Silicon carbide
• CPC Class Codes: C01B 32/977 Preparation from organic compounds containing silicon
• CPC Class Codes: C01F 17/218 Yttrium oxides or hydroxides
• CPC Class Codes: C01F 17/235 Cerium oxides or hydroxides
• CPC Class Codes: C01F 5/06 by thermal decomposition of magnesium compounds calcining magnesite or dolomite C04B2/10
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01G 19/00 Compounds of tin
• CPC Class Codes: C01G 25/00 : Compounds of zirconium
• CPC Class Codes: C01G 49/04 : Ferrous oxide [FeO]
• CPC Class Codes: C01G 49/06 : Ferric oxide [Fe2O3]
• CPC Class Codes: C01G 49/08 : Ferroso-ferric oxide [Fe3O4]
• CPC Class Codes: C01G 53/04 : Oxides; Hydroxides
• CPC Class Codes: C01P 2002/34 : perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/52 : containing elements as dopants
• CPC Class Codes: C01P 2004/54 : Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/61 : Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 : Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 : Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 : Surface area
• CPC Class Codes: C01P 2006/80 : Compositional purity
• CPC Class Codes: C04B 2235/3205 : Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
• CPC Class Codes: C04B 2235/3206 : Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 : Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3215 : Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3224 : Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3227 : Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 : Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3236 : Alkaline earth titanates
• CPC Class Codes: C04B 2235/3249 : containing also titanium oxide or titanates, e.g. lead zirconate titanate (PZT)
• CPC Class Codes: C04B 2235/3272 : Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3282 : Cuprates
• CPC Class Codes: C04B 2235/3286 : Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3293 : Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
• CPC Class Codes: C04B 2235/3427 : Silicates other than clay, e.g. water glass
• CPC Class Codes: C04B 2235/3804 : Borides
• CPC Class Codes: C04B 2235/3817 : Carbides
• CPC Class Codes: C04B 2235/3826 : Silicon carbides
• CPC Class Codes: C04B 2235/3852 : Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3895 : Non-oxides with a defined oxygen content, e.g. SiOC, TiON
• CPC Class Codes: C04B 2235/449 : Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/5409 : expressed by specific surface values
• CPC Class Codes: C04B 2235/5445 : submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5454 : nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/721 : Carbon content
• CPC Class Codes: C04B 35/62665 : Flame, plasma or melting treatment
• CPC Class Codes: C04B 41/89 : for obtaining at least two superposed coatings having different compositions

Abstract

A method of producing very high purity fine powders of oxides, carbides, nitrides, borides, chalcogenides, metals, and alloys. The purity of powders produced by the method exceeds 99.9%, preferably 99.999%, more preferably 99.99999%, and most preferably 99.9999999%. 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. Methods for producing such powders in high volume, low-cost, and reproducible quality are also outlined. The very high purity, fine powders are envisioned to be useful in various applications such as biomedical, sensor, electronic, electrical, photonic, thermal, piezo, magnetic, catalytic and electrochemical products.

Claims

1. A nanoscale powder with purity greater than 99.9% by metal basis and comprising silicon carbide, wherein the powder comprises of particles with mean size less than 250 nanometers.

2. The powder of claim 1, wherein the purity is greater than 99.999%.

3. The powder of claim 1 wherein the powder comprises particles having a mean size less than 100 nanometers.

4. A product prepared using the powder of claim 1.