Hydrolysis reactions of rare-earth and americium mononitrides

Hydrolysis reactions of AmN, NdN, DyN and their solid solutions with ZrN in moist atmospheres were examined at room temperature by means of weight measurements, X-ray diffraction and chemical analyses. The weight gains of the pure nitrides were saturated within 30 h to form hydroxides, M(OH)3. On the samples exposed to ambient air, an increase in carbon content was found, which must have been caused by the reaction of the hydroxides with CO2. The weight gains of (Zr0.9Am0.1)N and (Zr0.8Dy0.2)N were very slight and mainly due to water adsorption. For (Zr0.5Dy0.5)N, the weight gain and chemical analyses showed that about 30% of the sample reacted with moisture to form amorphous Dy(OH)3 and ZrO2. It was confirmed that ZrN is effective to stabilize AmN and DyN against moisture, and that the stabilization effect depends on the ZrN fraction in solid solutions.