Semi-Continuous Vapor Deposition Process for the Manufacture of Coated Particles
AssigneePneumatiCoat Technologies LLC
InventorsDavid M. King, Alan W. Weimer, Paul Lichty
Life of this patent
Estimating the term…
Abstract
A reactor for conducting vapor phase deposition process is disclosed. The reactor includes a reactive precursor reservoir beneath a powder reservoir and separated from it by valve means. A reactive precursor is charged into the reactive precursor reservoir and a powder is charged into the powder reservoir. The pressures are adjusted so that the pressure in the reactive precursor reservoir is higher than that of the powder reservoir. The valve means is opened, and the vapor phase reactant fluidized the powder and coats its surface. The powder falls into the reactive precursor reservoir. The apparatus permits vapor phase deposition processes to be performed semi-continuously.
Claims12
A reactor for performing vapor phase deposition on a powder, comprising
- 1. a powder reservoir;
- 2. a reactive precursor reservoir positioned below the powder reservoir;
- 3. valve means interposed between the powder reservoir and the reactive precursor reservoir, said valve means operable between an open and a closed position such that the powder reservoir is isolated from said reactive precursor reservoir when said valve means is in the closed position but when the valve means is in the open position, the powder reservoir is in communication with the reactive precursor reservoir such that a reactive precursor contained within the reactive precursor reservoir can flow into the powder reservoir and a powder contained within said powder reservoir can fall into the reactive precursor reservoir.
A vapor phase deposition process for applying a coating to the surface of a powder, comprising
- A. charging a powder to a powder reservoir;
- B. charging at least one reactive precursor to a reactive precursor reservoir positioned below the powder reservoir, and bringing the reactive precursor reservoir containing the reactive precursor(s) to conditions such that the reactive precursor(s) are in the vapor state and wherein the pressure in the reactive precursor reservoir is higher than the pressure in the powder reservoir;
- C. after steps A and B, discharging the reactive precursor vapor from the reactive precursor reservoir into the powder reservoir such that (1) the powder particles in the powder reservoir are contacted by the reactive precursor vapor and become at least partially fluidized thereby, (2) the reactive precursor(s) or reaction product thereof deposit at the surfaces of the powder particles and (3) the powder falls from the powder reservoir into the reactive precursor reservoir;
- and then
- D. removing the powder from the reactive precursor reservoir.
A process for applying one or more layers of a coating to a powder, wherein at least one of such layers is formed in a reaction cycle of X steps in which the powder is exposed sequentially to X vapor phase reagents in X reactors, where X is at least 2, and each step x of said X steps in each reaction cycle is performed by
- A. charging a powder from step x−1, or a starting powder or a coated powder from a previous reaction cycle when x=1, into an xth powder reservoir of an xth reactor;
- B. charging an xth reactive precursor to an xth reactive precursor reservoir positioned below the xth powder reservoir, and bringing the xth reactive precursor reservoir containing the xth reactive precursor to conditions such that the xth reactive precursor is in the vapor state and wherein the pressure in the xth reactive precursor reservoir is higher than the pressure in the xth powder reservoir;
- C. after steps A and B, discharging the xth reactive precursor from the xth reactive precursor reservoir into the xth powder reservoir such that (1) the powder particles in the xth powder reservoir are contacted by the xth reactive precursor vapor and become fluidized thereby, (2) the xth reactive precursor or a reaction product thereof deposits at the surfaces of the powder particles and (3) the powder then falls from the xth powder reservoir into the xth reactive precursor reservoir;
- then
- D. removing the powder from the xth reactive precursor reservoir and, when x<X, transferring the powder to an (x+1)th powder reservoir.
Dependencies are inferred from the claim text.