Sodium/Molybdenum Composite Metal Powders, Products Thereof, and Methods for Producing Photovoltaic Cells

Abstract

A method for producing a composite metal powder according to one embodiment of the invention may comprise: 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.

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 composite metal powder produced according to the method of  claim 1 . 
     
     
         13 . A method for producing a composite metal powder, comprising:
 providing a supply of molybdenum metal powder;   providing a supply of a sodium molybdate powder;   combining said molybdenum metal powder and said sodium molybdate powder with water to form a slurry;   feeding said slurry into a stream of hot gas; and   recovering the composite metal powder.   
     
     
         14 . A composite metal powder produced according to the method of  claim 13 . 
     
     
         15 . The composite metal powder product of  claim 14  comprising a Hall flowability in a range of about 30-35 seconds for 50 grams. 
     
     
         16 . The composite metal powder product of  claim 14  having a Scott density in a range of about 2 g/cc to about 3 g/cc. 
     
     
         17 . The composite metal powder product of  claim 14 , comprising from about 0.2% by weight to about 3.5% by weight retained sodium. 
     
     
         18 . The composite metal powder product of  claim 14  comprising less than about 6% by weight retained oxygen. 
     
     
         19 . 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; and 
 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.   
     
     
         20 . The method of  claim 19 , wherein said consolidating said composite metal powder comprises cold isostatic pressing. 
     
     
         21 . The method of  claim 19 , wherein consolidating comprises pressing said composite metal powder into a shape and sintering the shape. 
     
     
         22 . The method of  claim 21 , wherein said sintering is conducted in a hydrogen atmosphere. 
     
     
         23 . The method of  claim 22 , wherein said sintering is conducted at a temperature of less than about 825° C. 
     
     
         24 . The method of  claim 19 , wherein consolidating comprises hot isostatic pressing. 
     
     
         25 . A metal article produced by the method of  claim 19 . 
     
     
         26 . The metal article of  claim 25 , wherein said metal article comprises from about 0.2% by weight to about 3.5% by weight retained sodium. 
     
     
         27 . The metal article of  claim 25 , wherein said metal article comprises a sputter target. 
     
     
         28 . 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.   
     
     
         29 . The method of  claim 23 , wherein depositing a sodium/molybdenum metal layer comprises sputtering a target comprising a sodium/molybdenum metal matrix, sputtered material from the target forming said sodium/molybdenum metal layer. 
     
     
         30 . The method of  claim 28 , wherein depositing a sodium/molybdenum metal layer comprises:
 providing a supply of a composite metal powder comprising molybdenum and sodium;   depositing said composite metal powder on said substrate by thermal spraying.   
     
     
         31 . The method of  claim 28 , 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 printing.   
     
     
         32 . The method of  claim 28 , 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 evaporation.   
     
     
         33 . The method of  claim 28 , further comprising depositing a transparent conductive oxide layer on said junction partner layer. 
     
     
         34 . The method of  claim 33 , wherein said absorber layer comprises one or more selected from the group consisting of copper, indium, and selenium. 
     
     
         35 . The method of  claim 34 , wherein said junction partner layer comprises one or more selected from the group consisting of cadmium sulfide and zinc sulfide. 
     
     
         36 . 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.   
     
     
         37 . 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. 
     
     
         38 . 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.   
     
     
         39 . 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.