Reaction of Nitrogen with Uranium

Rates of reaction of nitrogen with uranium were determined by volumetric measurements in the temperature range 550°–900°C at atmospheric pressure. The reactions were found to follow a parabolic rate law with some deviations initially and also after the period of parabolic reaction. Surface reaction products formed in the temperature range 550°–750°C were identified by x‐ray diffraction studies to consist principally of with slight evidence of in some cases. Between 775° and 900°C the three nitrides , and were found in the surface reaction product. The parabolic rate constant for the reaction between 550° and 750°C was found to be . The activation energy, 25,500 cal/mole, has a probable error of ±1800 cal/mole. Between 775° and 900°C the parabolic rate constant is , where 15,100 ±2000 cal/mole is the energy of activation. It has not been determined if the change in rate constant near the temperature of the beta to gamma transformation in uranium has any special significance.