Vapor Deposition Process for the Manufacture of Coated Particles

Abstract

A process for conducting vapor phase deposition is disclosed. The process separates a series of reactions through a sequence of reaction reservoirs. In some particular embodiments, the reactor includes a reactive precursor reservoir beneath a powder reservoir separated 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.

What is claimed is: 
     
         1 . A vapor phase powder coating process for coating a powder surface, said process comprising:
 (a) placing a powder in a powder reservoir;   (b) producing a first reactive precursor vapor in a precursor reservoir that is operatively connected to said powder reservoir under conditions sufficient to at least partially fluidize the powder by the first reactive precursor vapor;   (c) discharging the powder from said powder reservoir into said precursor reservoir, thereby producing a first reactive precursor coated powder; and   (d) contacting the first reactive precursor coated powder with at least one other reactive precursor vapor under conditions sufficient to produce a coated powder.   
     
     
         2 . The vapor phase powder coating process of  claim 1 , wherein said precursor reservoir is located below said powder reservoir. 
     
     
         3 . The vapor phase powder coating process of  claim 2 , wherein said step of discharging the powder from said powder reservoir comprises allowing the powder to fall from said powder reservoir into said precursor reservoir. 
     
     
         4 . The vapor phase powder coating process of  claim 3 , wherein the pressure in said precursor reservoir is higher than the pressure in said powder reservoir. 
     
     
         5 . The vapor phase powder coating process of  claim 1 , wherein said process is an atomic layer deposition process, a molecular layer deposition process, or a chemical deposition process. 
     
     
         6 . The vapor phase powder coating process of  claim 1 , wherein said step of contacting the first reactive precursor coated powder with at least one other reactive precursor vapor comprises:
 producing a second reactive precursor vapor in a second precursor reservoir that is operatively connected to said precursor reservoir under conditions sufficient to at least partially fluidize the first reactive precursor coated powder by the second reactive precursor vapor; and   discharging the first reactive precursor coated powder from said precursor reservoir into said second precursor reservoir, thereby producing the coated powder from the reaction between the second reactive precursor and the first reactive precursor that is on the surface of the powder.   
     
     
         7 . The vapor phase powder coating process of  claim 1  further comprising the step of removing the first reactive precursor from said precursor reservoir prior to said step of contacting the first reactive precursor coated powder with at least one other reactive precursor vapor. 
     
     
         8 . An atomic or molecular layer deposition process for coating a powder surface, said process comprising:
 (a) placing a powder in a powder reservoir;   (b) producing a first reactive precursor vapor in a precursor reservoir that is operatively connected to said powder reservoir under conditions sufficient to at least partially fluidize the powder by the first reactive precursor vapor;   (c) discharging the powder from said powder reservoir into said precursor reservoir, thereby producing a first reactive precursor coated powder;   (d) optionally removing the first reactive precursor vapor from said precursor reservoir or transferring the first reactive precursor coated powder to a second powder reservoir;   (e) producing a second reactive precursor vapor in a second precursor reservoir that is operatively connected to said precursor reservoir or said second powder reservoir under conditions sufficient to at least partially fluidize the first reactive precursor coated powder by the second reactive precursor vapor;   (f) discharging the first reactive precursor coated powder from said precursor reservoir or said second powder reservoir into said second precursor reservoir to produce an atomic layer or a molecular layer coated powder,   
       wherein the atomic layer or the molecular layer on the surface of the powder is formed from a reaction between the second reactive precursor and the first reactive precursor that is on the surface of the first reactive precursor coated powder. 
     
     
         9 . The atomic or molecular layer deposition process of  claim 8 , wherein said precursor reservoir is located below said powder reservoir. 
     
     
         10 . The atomic or molecular layer deposition process of  claim 9 , wherein said step of discharging the powder from said powder reservoir comprises allowing the powder to fall from said powder reservoir into said precursor reservoir. 
     
     
         11 . The atomic or molecular layer deposition process of  claim 10 , wherein the pressure in said precursor reservoir is higher than the pressure in said powder reservoir. 
     
     
         12 . The atomic or molecular layer deposition process of  claim 8 , wherein said step (d) comprises optionally removing the first reactive precursor vapor from said precursor reservoir. 
     
     
         13 . The atomic or molecular layer deposition process of  claim 12 , wherein said second precursor reservoir is located below said precursor reservoir. 
     
     
         14 . The atomic or molecular layer deposition process of  claim 8 , wherein said step (d) comprises transferring the first reactive precursor coated powder to a second powder reservoir that located below said precursor reservoir. 
     
     
         15 . The atomic or molecular layer deposition process of  claim 14 , wherein said second precursor reservoir is located below said second powder reservoir. 
     
     
         16 . The atomic or molecular layer deposition process of  claim 8 , wherein said step of discharging the first reactive precursor coated powder from said precursor reservoir or said second powder reservoir into said second precursor reservoir comprises allowing the first reactive precursor coated powder to fall from said precursor reservoir or said second powder reservoir into said second precursor reservoir.