Liquid feed flame spray modification of nanoparticles

• US 7,700,152 B2
• Filed: 02/25/2005
• Issued: 04/20/2010
• Est. Priority Date: 02/27/2004
• Status: Expired due to Fees

• Current Assignee: Maxit Group (Compagnie De Saint-Gobain S.A.), Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Marchal, Julien, Rennesund, Roy, Azurdia, Jose, Laine, Richard M.
• Primary Examiner(s): Cleveland; Michael
• Assistant Examiner(s): VETERE, ROBERT A
• Application Number:
  US11/066,822
• Publication Number:
  US 20060087062A1
• Time in Patent Office: 1,880 Days
• Field of Search: 427/227, 427/215
• US Class Current: 427/212
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/145 After-treatment of oxides or hydroxides, e.g. pulverising, drying, decreasing the acidity
• CPC Class Codes: C01B 13/34 by oxidation or hydrolysis of sprayed or atomised solutions
• CPC Class Codes: C01F 7/021 After-treatment of oxides or hydroxides
• CPC Class Codes: C01F 7/027 Treatment involving fusion or vaporisation
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/34 hollow
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• 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 2004/84 one phase coated with the other
• CPC Class Codes: C01P 2004/86 Thin layer coatings, i.e. the coating thickness being less than 0.1 time the particle radius
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/322 Transition aluminas, e.g. delta or gamma aluminas
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 : Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3241 : Chromium oxides, chromates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3279 : Nickel oxides, nickalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/441 : Alkoxides, e.g. methoxide, tert-butoxide
• CPC Class Codes: C04B 2235/5409 : expressed by specific surface values
• CPC Class Codes: C04B 2235/5454 : nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/77 : Density
• CPC Class Codes: C04B 33/04 : Clay; Kaolin
• CPC Class Codes: C04B 35/10 : based on aluminium oxide
• CPC Class Codes: C04B 35/111 : Fine ceramics
• CPC Class Codes: C04B 35/6263 : characterised by their solids loadings, i.e. the percentage of solids
• CPC Class Codes: C04B 35/6264 : Mixing media, e.g. organic solvents
• CPC Class Codes: C04B 35/62665 : Flame, plasma or melting treatment
• CPC Class Codes: C04B 35/628 : Coating the powders or the macroscopic reinforcing agents
• CPC Class Codes: C04B 35/62813 : Alumina or aluminates
• CPC Class Codes: C04B 35/62818 : Refractory metal oxides
• CPC Class Codes: C04B 35/62821 : Titanium oxide
• CPC Class Codes: C04B 35/62826 : Iron group metal oxides
• CPC Class Codes: C04B 41/009 : characterised by the material treated
• CPC Class Codes: C04B 41/4537 : by the sol-gel process
• CPC Class Codes: C04B 41/4584 : Coating or impregnating of particulate or fibrous ceramic material C04B20/10, C04B35/628 take precedence
• CPC Class Codes: C04B 41/5027 : Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5032 : Aluminates aluminate spinels C04B41/5046
• CPC Class Codes: C04B 41/5041 : Titanium oxide or titanates
• CPC Class Codes: C04B 41/87 : Ceramics
• CPC Class Codes: C09C 1/407 : Aluminium oxides or hydroxides
• CPC Class Codes: C09C 1/42 : Clays
• CPC Class Codes: C23C 24/00 : Coating starting from inorganic powder spraying of the coating material in molten state C23C4/00; solid state diffusion C23C8/00 - C23C12/00
• CPC Class Codes: C23C 4/123 : Spraying molten metal
• CPC Class Codes: C23C 4/134 : Plasma spraying
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft

Abstract

Nano- and micron sized metal oxide and mixed metal oxide particles are injected into a high temperature region wherein the temperature is between about 400° C. and less than 2000° C., and collected as particles or as coatings wherein a particulate nature is substantially maintained. The particles are altered in at least one of phase, morphology, composition, and particle size distribution, and may achieve further changes in these characteristics by coinjection of metal oxide precursor in liquid form.

Claims

1. A process for the modification of particles comprising metal oxide and mixed metal oxides having a number average particle size of less than 100 μ

m, comprising;

a) injecting preformed particles in a flow of suspending medium through a high temperature zone having a temperature greater than 400°

C. and less than 2000°

C.;

b) optionally coinjecting a liquid composition comprising one or more metal oxide precursor compounds;

c) rapidly quenching the particles to obtain product particles or coatings of product particles wherein at least one of composition, phase, morphology, particle size, or particle size distribution is modified.

2. The process of claim 1, wherein said temperature is between 600°

C. and 1400°

C.

3. The process of claim 1, wherein minimally two different types of particles are co-injected and the product particles collected are substantially of a single type containing constituents of each of the different types of co-injected particles;

are particles of one type having particles of a second type fused thereto;

or are a mixture of these types of particles.

4. The process of claim 1, wherein the product particles, following at least partial quenching in step c), impact a target substrate and adhere thereto, substantially retaining their particulate nature and not forming a continuous coating.

5. The process of claim 1, wherein the step (c) further includes rapidly quenching the particles at a rate of no less than 500°

C. per second.

6. A process for the modification of particles comprising metal oxide and mixed metal oxides having a number average particle size of less than 100 μ

m, comprising;

a) injecting preformed particles in a flow of suspending medium through a high temperature zone having a temperature greater than 400°

C. and less than 2000°

C.;

b) coinjecting a liquid composition comprising one or more metal oxide precursor compounds;

c) rapidly quenching the particles to obtain product particles or coatings of product particles wherein at least one of composition, phase, morphology, particle size, or particle size distribution is modified.

7. The process of claim 6, wherein said metal oxide precursor is injected serially with relation to the point of injection of the preformed particles.

8. The process of claim 6, wherein the product particles collected in step c) comprise particles of uniform composition comprising the same metal oxide(s) of the preformed particles and metal oxide(s) derived from pyrolysis of the metal oxide precursor(s).

9. The process of claim 6, wherein the product particles collected in step c) comprise particles of at least two phases, at least one phase comprising metal oxide(s) derived from pyrolysis of the metal oxide precursor(s).

10. The process of claim 6, wherein the product particles comprise an outer phase enriched with metal oxide(s) derived from pyrolysis of the metal oxide precursor(s).

11. A process for the modification of particles comprising metal oxide and mixed metal oxides having a number average particle size of less than 100 μ

m, comprising;

a) injecting preformed particles in a flow of suspending medium through a high temperature zone having a temperature greater than 400°

C. and less than 2000°

C.;

b) optionally coinjecting a liquid composition comprising one or more metal oxide precursor compounds;

c) rapidly quenching the particles to obtain product particles or coatings of product particles wherein at least one of composition, phase, morphology, particle size, or particle size distribution is modified, wherein the preformed particles are of γ

-alumina, δ

-alumina, θ

-alumina, or mixtures thereof, and the particles collected in step c) are α

-alumina or are enriched with α

-alumina relative to the α

-alumina content of the preformed particles.

12. A process for preparing a high density sintered alumina article, comprising:

1) preparing sinterable product particles comprising α

-alumina by the process of claim 11;

2) preparing a green body from said sinterable particles; and

3) sintering said green body to produce an alumina article having a density of greater than 60% of theoretical fully dense alumina.

13. A process for the modification of particles comprising metal oxide and mixed metal oxides having a number average particle size of less than 100 μ

m, comprising;

a) injecting preformed particles in a flow of suspending medium through a high temperature zone having a temperature greater than 400°

C. and less than 2000°

C.;

b) optionally coinjecting a liquid composition comprising one or more metal oxide precursor compounds;

c) rapidly quenching the particles to obtain product particles or coatings of product particles wherein at least one of composition, phase, morphology, particle size, or particle size distribution is modified, wherein the preformed particles comprise particles of clay or ash.

14. The process of claim 13, wherein clay particles are the preformed particles, and the product particles comprise hollow spheres.