Method of making titanium based carbonitride alloys

Abstract

The present invention pertains to environment-friendly and economic preparation, handling, and spray drying of slurries for the production of titanium based carbonitride alloys. The slurry is based on ethanol and water and comprises raw materials for the end product as well as polyethylene glycol (PEG) and a low concentration of polyethylenimine (PEI). The concentration of PEI is from about 0.1 to about 0.7% of the raw material weight. Hereby, slurries with low viscosities are produced which require less use of ethanol and energy, as well as manpower and equipment time in their preparation, handling, and spray drying.

1 . Method of making titanium based carbonitride alloys with a binder phase based on Co and/or Ni by powder metallurgical methods comprising wet milling in alcohol, water or a mixture thereof of powder and pressing agent to form a slurry, said slurry including from about 0.1 to about 0.7 wt % of a polyethylenimine-based polyelectrolyte, the pressing agent being polyethylene glycol in an amount of from about 1.0 to about 5.0% of the powder raw material weight, drying the slurry to form a granulate by spray drying, pressing the granulate to form bodies of desired shape and dimension and sintering.  
     
     
         2 . The method of  claim 1  wherein said polyethylenimine-based polyelectrolyte is added in an amount of from about 0.25 to about 0.40 wt % to the slurry.  
     
     
         3 . The method of  claim 1  wherein the average molecular weight of the polyethylenimine-based polyelectrolyte is from about 1,000 to about 50,000.  
     
     
         4 . The method of  claim 1  wherein the average molecular weight of the polyethylenimine-based polyelectrolyte is from about 10,000 to about 30,000.  
     
     
         5 . In a slurry with viscosity suitable for spray drying intended for the manufacturing of titanium based carbonitride alloy bodies, the improvement comprising said slurry also containing from about 0.1 to about 0.7 wt % of a polyethylenimine-based polyelectrolyte and polyethylene glycol in an amount of from about 1.0 to about 5.0% of the powder raw material weight.  
     
     
         6 . In the slurry of  claim 5  wherein said slurry contains from about 0.25 to about 0.4 wt % of a polyethylenimine-based polyelectrolyte.  
     
     
         7 . In the slurry of  claim 5  wherein the average molecular weight of the polyethylenimine-based polyelectrolyte is from about 1,000 to about 50,000.  
     
     
         8 . In the slurry of  claim 7  wherein the average molecular weight of the polyethylenimine-based polyelectrolyte is from about 10,000 to about 30,000.