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The reaction kinetics of ZrN and HfN immersed in a quaternary salt of composition of 28.5% LiCl–36.3% KCl–29.4% NaCl–5.8% UCl 3 (in weight percent) were assessed. Coupons of ZrN and HfN were exposed to the quaternary salt at 525–900 °C for 4–485 h. The reaction kinetics of the salt-refractory interactions were assessed through physical and microstructural characterization including scanning electron microscopy, X-ray diffraction and mass spectrometry. The results indicated that ZrN and HfN lose weight under all conditions investigated. While multiple mechanisms were evident, it is proposed that dissolution and oxidation were the dominant reactions that influence the weight loss. For the overall reaction, negative apparent activation energy values of −46 and −28 kJ/mol were observed in ZrN and HfN, respectively. These seemingly anomalous activation energies were associated with the simultaneous occurrence of electrochemical dissolution and surface oxide formation.

A high energy ball milling process was used to produce dysprosium nitride and cerium nitride powders at room temperature. Dysprosium and cerium metal flakes were milled in a 275 kPa nitrogen atmosphere for 24 h at ambient temperatures. X-ray diffraction confirmed the formation of phase pure dysprosium nitride and cerium nitride powders. The median particle size of the resultant dysprosium nitride was measured as 4 μm using a laser scattering technique. The particle size of the cerium nitride was not measured due to its reactive nature.

A high energy, low-temperature, ball-milling route was used to directly produce uranium nitride. Pure uranium metal particles (∼100 μm) were ball milled under a 420 kPa nitrogen atmosphere for 24 h at ambient temperature to yield phase pure U 2 N 3 powder as confirmed by X-ray diffraction and energy dispersive spectroscopy. The median particle size was measured to be approximately 6 μm.