Characteristics of uranium carbonitride microparticles synthesized using different reaction conditions

Three sets of experimental conditions were tested to synthesize uranium carbonitride (UC1−xNx) kernels from gel-derived urania-carbon microspheres. Primarily, three sequences of gases were used, N2 to N2-4%H2 to Ar, Ar to N2 to Ar, and Ar-4%H2 to N2-4%H2 to Ar-4%H2. Physical and chemical characteristics such as geometrical density, phase purity, and chemical compositions of the synthesized UC1−xNx were measured. Single-phase kernels were commonly obtained with densities generally ranging from 85% to 93% TD and values of x as high as 0.99. In-depth analysis of the microstrutures of UC1−xNx has been carried out and is discussed with the objective of large batch fabrication of high density UC1−xNx kernels.