Ceramic lamellar composites

Abstract

Disclosed herein is a method of: placing between a cooling element and an opposing surface a slurry of: a dielectric powder containing barium titanate, a dispersant, a binder, and water; maintaining the cooling element at a temperature below the opposing surface to cause the formation of ice platelets perpendicular to the surface of the cooling element and having the powder between the platelets; subliming the ice platelets to create voids; sintering the powder to form the dielectric material; and filling the voids with the polymeric material. The process can produce a composite having: a sintered dielectric material of barium titanate and platelets of a polymeric material embedded in the dielectric material. Each of the platelets is perpendicular to a surface of the composite.

1 . A composite comprising:
 a sintered dielectric material comprising barium titanate; and   platelets of a polymeric material embedded in the dielectric material;
 wherein each of the platelets is perpendicular to a surface of the composite. 
   
     
     
         2 . The composite of  claim 1 , wherein the polymeric material is an epoxy, a polyurethane, or a silicone. 
     
     
         3 . The composite of  claim 1 , wherein the composite has a dielectric constant of at least about 500 in a direction perpendicular to the surface. 
     
     
         4 . The composite of  claim 1 , wherein the composite is made by a method comprising:
 placing between a cooling element and an opposing surface a slurry comprising: a powder of the dielectric material, a dispersant, a binder, and water;   maintaining the cooling element at a temperature below the opposing surface to cause the formation of ice platelets perpendicular to the surface of the cooling element and having the powder between the platelets;   subliming the ice platelets to create voids;   sintering the powder to form the dielectric material; and   filling the voids with the polymeric material.   
     
     
         5 . The composite of  claim 4 , wherein the opposing surface is a second cooling element. 
     
     
         6 . The composite of  claim 4 , wherein the difference in temperature between the cooling element and the opposing surface is about 5 to about 70° C. 
     
     
         7 . The composite of  claim 4 , wherein the cooling element is templated to promote the formation of platelets that are parallel to each other. 
     
     
         8 . A device comprising:
 the composite of  claim 1 ; and   two electrodes in electrical contact with the composite.   
     
     
         9 . The device of  claim 8 , wherein the electrodes are perpendicular to the platelets. 
     
     
         10 . The device of  claim 8 , wherein the device is a capacitor. 
     
     
         11 . A method comprising:
 placing between a cooling element and an opposing surface, a slurry comprising: a powder of a dielectric material comprising barium titanate, a dispersant, a binder, and water;   maintaining the cooling element at a temperature below the opposing surface to cause the formation of ice platelets perpendicular to the surface of the cooling element and having the powder between the platelets;   subliming the ice platelets to create voids;   sintering the powder to form the dielectric material; and   filling the voids with the polymeric material.   
     
     
         12 . The method of  claim 11 , wherein the polymeric material is an epoxy, a polyurethane, or a silicone. 
     
     
         13 . The method of  claim 11 , wherein the opposing surface is a second cooling element. 
     
     
         14 . The method of  claim 11 , wherein the difference in temperature between the cooling element and the opposing surface is about 5 to about 70° C. 
     
     
         15 . The method of  claim 11 , wherein the cooling element is templated to promote the formation of platelets that are parallel to each other.