Kinetics of the Reaction of UC2 and Nitrogen from 1500° to 1700°C

The kinetics of the reaction of UC₂ spheres with nitrogen was studied from 1500° to 1700°C. A metallographic method was used to determine the time-dependent conversion of UC₂ to U(C,N) and free C. The conversion appeared to be controlled by the diffusion of solid carbon in solution to sites where it could precipitate as free carbon. These sites were the surface of the sphere and particles of free carbon that existed within the original UC₂. An increased distribution of these internal sites decreased the distance for carbon diffusion and resulted in an increased rate of reaction. The UC₂ appeared to undergo a very rapid initial reaction that resulted in the uptake of 1 to 5 at.% nitrogen in the UC₂ at these temperatures.