Oxygen Solubility of Rarc Earth Mctals.

1.氧分析利用本实验室的氧分析装置，研究了氧含量随熔剂和温度变化的分析方法。在实验结果的基础上，获得了在2873K下进行准确氧分析的最佳条件，对于Nd3+，TiN浓度大于0.3摩尔分数，对于Pr，TiN浓度大于0.5摩尔分数。氧在固体Nd3+和Pr3+中的溶解度用扩散电偶法和固体电泳法测定了氧在固体Nd3+和Pr中的溶解度。氧在固体钕中的溶解度分别为0.0774、0.0997、0.122、0.136、0.148和0.161。X-射线衍射仪分析表明，在整个实验温度范围内，NdO为含固体钕的平衡氧化物相。另一方面，氧在Pr中的溶解度在1113K时为0.0595质量%。氧在液态钕中的溶解度通过将金属熔体与氧化钕(ND_2O_3)在密封在石英胶囊中的钼坩埚中平衡来测量氧在液态钕中的溶解度。氧的溶解度分别为0.182质量%(137K)、0.296质量%(1473K)和1.46质量%(1773K)。经X-射线衍射仪分析，在1473K时，Nd2O_3为与液态钕相平衡的氧化物相。

1. Oxygen AnalysisUsing the device in our laboratory, the analytical procedures of oxygen content in neodymium and praseodymium were studied as a function of flux and temperature. On the basis of the experimental results, optimum conditions for accurate oxygen analysis were obtained at 2873 K with tin concentrations above 0.3 mole fraction for neodymium and above 0.5 mole fraction in the case of praseodymium.2. Oxygen Solubility in Solid Neodymium and PraseodymiumThe oxygen solubility in solid neodymium and praseodymium were determined by diffusion couple method and solid state erectrotransport. Oxygen solubilities in solid neodymium were 0.0774 mass%(1023K), 0.0997 mass% (1073 K), 0.122 mass% (1123 K), 0.136 mass% (1173 K), 0.148 mass% (1223 K) and 0.161 mass% (1248 K) respectively. By the X-ray diffraction analysis, NdO was identified as the equilibrium oxide phase with solid neodymium in the whole temperature range of these experiments. On the other hand, solubility of the oxygen in praseodymium was 0.0595 mass% at 1113 K.3. Oxygen Solubility in Liquid NeodymiumSolubility of oxygen in liquid neodymium was measured by equilibrating the metallic melt with the neodymium oxide (Nd_2O_3) in a molybdenum crucible sealed in quartz capsule. Oxygen solubilities of 0.182 mass% (1373 K), 0.296 mass% (1473 K), and 1.46 mass% (1773 K) were obtained respectively. By the X-ray diffraction analysis, Nd_2O_3 was identified as the equilibrium oxide phase with liquid neodymium at 1473 K.