Metal powder composition for laser sintering

Abstract

A powder blend for use in laser sintering and a method for forming tough, strong, wear-resistant, corrosion-resistant infiltrated metal products are provided. The powder blend comprises a steel alloy, a polymeric binder and a high melting temperature fine particulate which are blended together, then applied layer by layer to a working surface in a laser sintering system, exposed a layer at a time to fuse together the powder until a green part of high strength is formed, and then the green part is infiltrated with a metal infiltrant in a non-reducing gas atmosphere at an effective temperature for an effective period of time. The preferred steel is a mild steel alloy.

1 . A powder blend for use in a laser sintering process comprising a polymeric binder, a high melting temperature fine particulate and a steel alloy selected from the group consisting of a mild steel alloy, a carbon steel and a stainless steel.  
     
     
         2 . The powder blend according to  claim 1  wherein the steel alloy ranges in size from less than about 90 microns to about 4 microns.  
     
     
         3 . The powder blend according to  claim 2  wherein the steel alloy ranges in size from less than about 75 microns to about 8 microns.  
     
     
         4 . The powder blend according to  claim 2  wherein the steel alloy is less than about 45 microns.  
     
     
         5 . The powder blend according to  claim 1  wherein the steel alloy is spherical.  
     
     
         6 . The powder blend according to  claim 2  wherein the high melting temperature fine particulate has a particle size less than about 10 microns.  
     
     
         7 . The powder blend according to  claim 6  wherein the high melting temperature fine particulate has a particle size less than about 2 microns.  
     
     
         8 . The powder blend according to  claim 7  wherein the high melting temperature fine particulate comprises greater than about 5 weight percent and less than about 15 weight percent of the powder blend.  
     
     
         9 . The powder blend according to  claim 8  wherein the high melting temperature fine particulate comprises about 8 weight percent of the powder blend.  
     
     
         10 . The powder blend according to  claim 1  wherein the polymeric binder is a thermoplastic or a thermoset.  
     
     
         11 . The powder blend according to  claim 1  wherein the polymeric binder is selected from the group consisting of polyethylene, polypropylene, polyacetal, polymethacrylate, polyvinylacetate, nylon, wax, phenolic and combinations thereof.  
     
     
         12 . The powder blend according to  claim 11  wherein the polymeric binder is nylon.  
     
     
         13 . The powder blend according to  claim 12  wherein the nylon is one selected from the group consisting of polymers and co-polymers of nylon 6, nylon 9, nylon 10, nylon 11, and nylon 12.  
     
     
         14 . The powder blend according to  claim 1  further comprising a flow agent.  
     
     
         15 . The powder blend according to  claim 14  wherein the flow agent is fumed silica.  
     
     
         16 - 31 . canceled  
     
     
         32 . The powder blend according to  claim 9  wherein the high melting temperature fine particulate is tungsten carbide.  
     
     
         33 . canceled