Methods for in situ deposition of coatings and articles produced using same

Abstract

Methods for depositing a coating on a metal surface can include heating a metal surface to a temperature not greater than its melting point; while heating the metal surface, applying a vacuum thereto; and while heating the metal surface, releasing the vacuum and backfilling with a first purge gas, where the first purge gas is reactive with the heated metal surface so as to deposit at least one layer of a coating thereon. The present methods can be used to deposit a coating in situ during the fabrication of solar receivers, in which the solar receivers contain an annulus defined by a metal tube as the inner surface and a material that is at least partially transparent to solar radiation as the outer surface.

1 . A method for depositing a coating on a metal surface, the method comprising:
 heating a metal surface to a temperature not greater than its melting point;   while heating the metal surface, applying a vacuum thereto; and   while heating the metal surface, releasing the vacuum and backfilling with a first purge gas;
 wherein the first purge gas is reactive with the heated metal surface so as to deposit at least one layer of a coating thereon. 
   
     
     
         2 . The method of  claim 1 , further comprising:
 after depositing the coating and while heating the metal surface, re-applying a vacuum thereto.   
     
     
         3 . The method of  claim 2 , further comprising:
 while heating the metal surface, depositing at least one additional layer of the coating by releasing the vacuum and backfilling with a second purge gas.   
     
     
         4 . The method of  claim 3 , wherein the first purge gas and the second purge gas are the same. 
     
     
         5 . The method of  claim 3 , wherein the first purge gas and the second purge gas are different. 
     
     
         6 . The method of  claim 1 , wherein the temperature is at least about 400° C. 
     
     
         7 . The method of  claim 1 , wherein the first purge gas is selected from the group consisting of air, water vapor, oxygen, carbon dioxide, carbon monoxide, nitrogen, fluorine, chlorine, bromine, iodine, hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, boron trifluoride, boron trichloride, boron tribromide, silicon tetrafluoride, sulfur hexafluoride, sulfur tetrafluoride, phosphorus trifluoride, phosphorus pentafluoride, nitrogen trifluoride, nitrous oxide, nitric oxide, nitrogen dioxide, dinitrogen tetroxide, diimide, hydrogen, gaseous organic compounds, and any combination thereof. 
     
     
         8 . The method of  claim 1 , wherein the coating comprises at least one of an oxide coating, a nitride coating, a carbide coating or a fluoride coating. 
     
     
         9 . The method of  claim 1 , wherein the first purge gas further comprises a diluent gas that is not reactive with the metal surface. 
     
     
         10 . A method for depositing a coating on a solar receiver, the method comprising:
 applying a vacuum to an annulus having an outer surface defined by a material that is at least partially transparent to solar radiation and an inner surface that is defined by a metal tube;   heating the metal tube, while applying the vacuum thereto, to a temperature not greater than its melting point; and   while heating the metal tube, releasing the vacuum and backfilling with a first purge gas;
 wherein the first purge gas is reactive with the heated metal tube so as to deposit at least one layer of a coating thereon. 
   
     
     
         11 . The method of  claim 10 , further comprising:
 after depositing the coating and while heating the metal tube, re-applying a vacuum to the annulus.   
     
     
         12 . The method of  claim 11 , further comprising:
 sealing the annulus so as to maintain the vacuum therein.   
     
     
         13 . The method of  claim 11 , further comprising:
 while heating the metal tube, depositing at least one additional layer of the coating by releasing the vacuum and backfilling with a second purge gas.   
     
     
         14 . The method of  claim 13 , wherein the first purge gas and the second purge gas are the same. 
     
     
         15 . The method of  claim 13 , wherein the first purge gas and the second purge gas are different. 
     
     
         16 . The method of  claim 10 , wherein the material that is at least partially transparent to solar radiation comprises a glass. 
     
     
         17 . The method of  claim 10 , wherein the temperature is at least about 400° C. 
     
     
         18 . The method of  claim 10 , wherein the first purge gas is selected from the group consisting of air, water vapor, oxygen, carbon dioxide, carbon monoxide, nitrogen, fluorine, chlorine, bromine, iodine, hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, boron trifluoride, boron trichloride, boron tribromide, silicon tetrafluoride, sulfur hexafluoride, sulfur tetrafluoride, phosphorus trifluoride, phosphorus pentafluoride, nitrogen trifluoride, nitrous oxide, nitric oxide, nitrogen dioxide, dinitrogen tetroxide, diimide, hydrogen, gaseous organic compounds, and any combination thereof. 
     
     
         19 . The method of  claim 10 , wherein the coating comprises at least one of an oxide coating, a nitride coating, a carbide coating or a fluoride coating. 
     
     
         20 . The method of  claim 10 , wherein the first purge gas further comprises a diluent gas that is not reactive with the metal tube. 
     
     
         21 . The method of  claim 10 , wherein the metal tube comprises a metal selected from the group consisting of carbon steel, stainless steel, and any combination thereof. 
     
     
         22 . A solar receiver prepared by the process of  claim 10 . 
     
     
         23 . The solar receiver of  claim 22 , further comprising:
 a heat transfer fluid located within the interior space of the metal tube.   
     
     
         24 . The solar receiver of  claim 22 , wherein the coating comprises at least one of an oxide coating, a nitride coating, a carbide coating or a fluoride coating. 
     
     
         25 . The solar receiver of  claim 22 , wherein the coating comprises a nanostructured coating.