Reduction Expansion Synthesis of Sintered Metal

Abstract

The disclosure provides a method for generating a solid metal object. Initially, a reductant material and a metal precursor particle mixture are arranged in a high temperature furnace that is filled with a chemically inert atmosphere. A temperature of the high temperature furnace is held above the decomposition temperature of the reductant but below a melting point of the metal precursor particle mixture for a predetermined duration to generate the solid metal object. At this stage, the generated metal object is cooled in the inert atmosphere.

What is claimed is: 
     
         1 . A method of generating a solid metal object comprising:
 arranging a reductant material and a metal precursor particle mixture in a high temperature furnace that is filled with a chemically inert atmosphere;   holding a temperature of the high temperature furnace above the decomposition temperature of the reductant but below a melting point of the metal precursor particle mixture for a predetermined duration to generate the solid metal object; and   cooling the generated metal object in the inert atmosphere.   
     
     
         2 . The method of  claim 1  where the high temperature furnace bakes the reductant and metal precursor particle mixture in order to:
 generate a chemical radical species by decomposing the reductant material; and 
 expose the metal precursor particle mixture within the inert atmosphere to the chemical radical species needed to generate the solid metal object. 
 
     
     
         3 . The method of  claim 1  where the inert atmosphere is nitrogen or argon. 
     
     
         4 . The method of  claim 1  where the reductant material is urea. 
     
     
         5 . The method of  claim 1  where the reductant material is a petroleum gel. 
     
     
         6 . The method of  claim 1  where the metal precursor particle mixture comprises a metal oxide and metal particles. 
     
     
         7 . The method of  claim 6  where a weight ratio of the metal oxide and the metal particles in the metal precursor particle mixture is approximately 1 to 1. 
     
     
         8 . The method of  claim 6  where the metal particles in the metal precursor particle mixture include more than one type of metal. 
     
     
         9 . The method of  claim 8  where the more than one type of metal includes at least two metals of group consisting of iron, nickel, and chromium. 
     
     
         10 . The method of  claim 8  where the metal oxide includes particles of nano-scale and the metal particles are micron-scale. 
     
     
         11 . The method of  claim 8  where the metal particles includes nano-scale metal particles and micron-scale metal particles. 
     
     
         12 . The method of  claim 6  where the metal precursor particle mixture further comprises molecular precursors. 
     
     
         13 . The method of  claim 6  further comprising grinding the metal precursor particle mixture to combine the metal oxide and the metal particles. 
     
     
         14 . The method of  claim 1  where approximately 99% of air is flushed from the high temperature furnace by the flow of inert atmosphere. 
     
     
         15 . The method of  claim 1  where prior to heating, the metal particle precursor is arranged above, and within two centimeters, of a bed of the reductant material. 
     
     
         16 . The method of  claim 1  where the metal precursor particle mixture is compressed or molded.