Sodium/molybdenum composite metal powders, products thereof, and methods for producing photovoltaic cells

Abstract

A method for producing a metal article may include: Producing a supply of a composite metal powder by: providing a supply of molybdenum metal powder; providing a supply of a sodium compound; combining the molybdenum metal powder and the sodium compound with a liquid to form a slurry; feeding the slurry into a stream of hot gas; and recovering the composite metal powder; and consolidating the composite metal powder to form the metal article, the metal article comprising a sodium/molybdenum metal matrix. Also disclosed is a metal article produced accordance with this method.

1 . A method for producing a composite metal powder, comprising:
 providing a supply of molybdenum metal powder;   providing a supply of a sodium compound;   combining said molybdenum metal powder and said sodium compound with a liquid to form a slurry;   feeding said slurry into a stream of hot gas; and   recovering the composite metal powder, said composite metal powder comprising sodium and molybdenum.   
     
     
         2 . The method of  claim 1 , wherein providing a supply of a sodium compound comprises providing a supply of sodium molybdate powder. 
     
     
         3 . The method of  claim 1 , wherein feeding said slurry into a stream of hot gas comprises atomizing said slurry and contacting said atomized slurry with the stream of hot gas. 
     
     
         4 . The method of  claim 1 , wherein combining said molybdenum metal powder and said sodium compound with a liquid comprises combining said molybdenum metal powder and said sodium compound with water to form a slurry. 
     
     
         5 . The method of  claim 1 , wherein said slurry comprises between about  15 % to about  25 % by weight liquid. 
     
     
         6 . The method of  claim 1 , further comprising:
 providing a supply of a binder material; and   combining said binder material with said molybdenum metal powder, said sodium compound, and said water to form a slurry.   
     
     
         7 . The method of  claim 6 , wherein said binder comprises one or more from the selected from the group consisting of polyvinyl alcohol and carbowax. 
     
     
         8 . The method of  claim 6 , wherein said sodium compound comprises sodium molybdate and wherein said slurry comprises between about 15% to about 25% by weight liquid, from about 0% to about 2% by weight binder, from about 1% by weight to about 15% sodium molybdate, and from about 58% by weight to about 84% by weight molybdenum metal powder. 
     
     
         9 . The method of  claim 6 , further comprising heating the recovered composite metal powder at a temperature sufficient to drive-off substantially all of said binder. 
     
     
         10 . The method of  claim 9 , wherein said heating further comprises heating in a hydrogen atmosphere. 
     
     
         11 . The method of  claim 10 , wherein said heating in a hydrogen atmosphere is conducted at a temperature in a range of about 500° C. to about 825° C. 
     
     
         12 . A sodium/molybdenum composite metal powder comprising a substantially homogeneous dispersion of sodium and molybdenum sub-particles that are fused together to form individual particles of said composite metal powder. 
     
     
         13 . The sodium/molybdenum composite metal powder of claim comprising a Hall flowability in a range of about 30-35 seconds for 50 grams. 
     
     
         14 . The sodium/molybdenum composite metal powder product of  claim 12  having a Scott density in a range of about 2 g/cc to about 3 g/cc. 
     
     
         15 . The sodium/molybdenum composite metal powder product of  claim 12 , comprising from about 0.2% by weight to about 3.5% by weight retained sodium. 
     
     
         16 . The sodium/molybdenum composite metal powder product of  claim 12  comprising less than about 6% by weight retained oxygen. 
     
     
         17 . A method for producing a metal article, comprising:
 producing a supply of a composite metal powder by:
 providing a supply of molybdenum metal powder; 
 providing a supply of a sodium compound; 
 combining said molybdenum metal powder and said sodium compound with a liquid to form a slurry; 
 feeding said slurry into a stream of hot gas; 
 recovering the composite metal powder; and 
   consolidating said composite metal powder to form the metal article, said metal article comprising a sodium/molybdenum metal matrix.   
     
     
         18 . The method of  claim 17 , wherein said consolidating said composite metal powder comprises cold isostatic pressing. 
     
     
         19 . The method of  claim 17 , wherein consolidating comprises pressing said composite metal powder into a shape and sintering the shape. 
     
     
         20 . The method of  claim 19 , wherein said sintering is conducted in a hydrogen atmosphere. 
     
     
         21 . The method of  claim 20 , wherein said sintering is conducted at a temperature of less than about 825° C. 
     
     
         22 . The method of  claim 17 , wherein consolidating comprises hot isostatic pressing. 
     
     
         23 . A method for producing a photovoltaic cell, comprising:
 providing a substrate;   depositing a sodium/molybdenum metal layer on said substrate;   depositing an absorber layer on said sodium/molybdenum metal layer; and   depositing a junction partner layer on said absorber layer;   wherein depositing a sodium/molybdenum metal layer comprises:   providing a supply of a composite metal powder comprising molybdenum and sodium; and   depositing said composite metal powder on said substrate by thermal spraying, by printing, or by evaporation.   
     
     
         24 . A method for depositing a film on a substrate, comprising:
 providing a supply of a composite metal powder comprising molybdenum and sodium;   depositing said composite metal powder on said substrate by thermal spraying.   
     
     
         25 . A method for depositing a film on a substrate, comprising sputtering a target comprising a sodium/molybdenum metal matrix, sputtered material from the target forming said sodium/molybdenum metal layer. 
     
     
         26 . A method for forming a coating on a substrate, comprising:
 providing a supply of a composite metal powder comprising molybdenum and sodium;   mixing said supply of composite metal powder with a vehicle; and   depositing the mixture of the composite metal powder and the vehicle on said substrate by printing.   
     
     
         27 . A method for depositing a film on a substrate, comprising:
 providing a supply of a composite metal powder comprising molybdenum and sodium;   depositing said composite metal powder on said substrate by evaporation.