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US 5,876,793 AGranted
Fine powders and method for manufacturing
AssigneeUltramet
InventorsAndrew Sherman, Victor Arrietta
Life of this patent
Estimating the term…
Abstract
The invention relates to the encapsulation of Geldhart class C substrate powders with a coating of metal, binder, or sintering aid. Encapsulation is achieved using chemical vapor deposition techniques in a recirculating fast-fluidized or turbulent fluidization flow bed reactor. Thin, smooth, generally uniform, fully encapsulating coatings are produced on the fine substrate particles. The coated Geldhart class C particles, and products made therefrom, exhibit excellent improved physical properties.
Claims26
A method of coating Geldhart class C particulate matter which comprises:
- establishing a heated reaction zone;
- selecting a plating reactant and establishing a vapor phase stream including said plating reactant flowing generally upwardly through said reaction zone at a predetermined rate;
- selecting said Geldhart class C particulate matter, said Geldhart class C particulate matter having a cohesive nature, and introducing said Geldhart class C particulate matter into said heated reaction zone to establish a fluidized bed;
- allowing said plating reactant to react in said reaction zone and form a coating on said Geldhart class C particulate matter to form coated particulate matter;
- adjusting said predetermined rate of said vapor phase stream to operate said fluidized bed in a fast-fluidized or turbulent fluidized flow regime;
- allowing said coated particulate matter to be carried upwardly out of said reaction zone by said vapor phase stream;
- collecting said coated particulate matter downstream from said reaction zone, and separating said coated particulate matter from said vapor phase stream;
- and
- maintaining said coated particulate matter separate from said vapor phase stream while introducing at least a part of such separated coated particulate matter back into said fluidized bed.
6 more elements
A method of coating particulate matter which comprises:
- establishing a heated reaction zone;
- selecting a plating reactant and establishing a vapor phase stream including said plating reactant flowing generally upwardly through said reaction zone at a predetermined rate;
- selecting particulate matter which comprises a Geldhart Class C powder and introducing said particulate matter into said heated reaction zone to form a fluidized bed;
- allowing said particulate matter to be carried through said reaction zone by said vapor phase stream;
- allowing said plating reactant to react in said reaction zone and form a coating on said particulate matter to form coated particulate matter;
- adjusting the predetermined rate of said vapor phase stream to a rate which is at least sufficient to operate said fluidized bed in a fast-fluidized or turbulent fluidized flow regime;
- collecting said coated particulate matter downstream from said reaction zone in a packed bed in a collection zone;
- recirculating a portion of said coated particulate matter directly from said packed bed to said fluidized bed;
- and
- harvesting at least a portion of said coated particulate matter from said collection zone.
7 more elements
A fluidized bed reactor process for coating Geldhart class C particulates comprising:
- selecting Geldhart class C particulate material;
- establishing a first fluidized bed of such Geldhart class C particulate material;
- establishing a heated reaction zone in said first fluidized bed;
- maintaining said first fluidized bed by injecting a fluidizing stream of vapor, including plating reactant, into said first fluidized bed at a first velocity, said first velocity being sufficient to operate said first fluidized bed above the bubbling fluidized bed regime;
- allowing said plating reactant to form a coating on said Geldhart class C particulate material in said heated reaction zone to produce coated particulate material;
- collecting at least a substantial portion of said coated particulate material downstream from said reaction zone in a packed bed in a collection zone;
- transporting at least a part of said packed bed from said collection zone to said heated reaction zone.
4 more elements
A method of coating particulate matter which comprises:
- establishing a heated reaction zone;
- selecting a plating reactant and establishing a vapor phase stream including said plating reactant flowing generally upwardly through said reaction zone at a predetermined rate;
- selecting Geldhart class C particulate matter, said Geldhart class C particulate matter having a cohesive nature, and introducing said Geldhart class C particulate matter into said heated reaction zone to establish a fluidized bed comprising said Geldhart class C particulate matter;
- allowing said plating reactant to react in said reaction zone and form a coating on said Geldhart class C particulate matter to form coated particulate matter;
- adjusting said predetermined rate of said vapor phase stream to operate said fluidized bed in a fast-fluidized or turbulent fluidized flow regime;
- and
- recovering said coated particulate matter from said reaction zone.
4 more elements
Dependencies are inferred from the claim text.