Production of 28 μm zirconium carbide kernels using the internal gelation process and microfluidics

Abstract Studies using internal gelation and microfluidics have shown that the production of sintered spheres with diameters below 200 μm is possible. The addition of carbon can be problematic because of slow flow rates (100 μL/min) and long run times (4 h). However, a solution of dispersed carbon, Cabot’s TPX-101, was successfully used with solutions of zirconyl nitrate, urea, and hexamethylenetetramine to make zirconium microspheres with carbon. A simple carbothermic reduction using a maximum temperature of 2073 K and ultrahigh purity argon produced zirconium carbide kernels with an average diameter of 28 μm and a standard deviation of 2.3 μm.