Deoxidaton of Rare Earth Metals by Halide Flux Treatmwent

1.用几种卤化物助熔剂进行了初步的脱氧实验。在此基础上，考察了所用助熔剂对脱氧能力的影响，验证了该方法的有效性。REF_3 - RE-oxide （RE=Nd, Pr）准二元平衡REF_3粉末和RE-oxide球团在石墨坩埚中带电，在1723 K氩气下加热一段时间。然后，将坩埚从熔炉中取出，并通过喷射氦气快速淬火。在两个实验中都观察到熔化部分和固体部分两种相，并对两者进行了X-my衍射分析。在两部分均检测到NdOF或PrOF峰。RE - REF_3 - RE_20_3准三元体系随着REOF相的确定，进行了一系列新的实验来确定RE - REF_3 - REOF准三元平衡。利用这些结果和RE- o体系的部分相图，建立了RE- REF_3 - RE_20_3准三元体系在1723 K时的相图。根据相图对两种稀土金属的脱氧反应进行了估计。脱氧实验用NdF_3或PrF_3作为卤化物熔剂进行脱氧实验，以验证估计的脱氧反应。通过卤化物熔剂处理可以成功地降低氧含量。因此，卤化物熔剂处理不仅是一种简单的工艺，而且是一种有效的脱氧方法。

1.Preliminary Experiments by Various Halide FluxesPreliminary deoxidation experiments were conducted by using several kind of halide fluxes. Based on the above results, effect of used fluxes on deoxidation ability was investigated and effectiveness of this method was confirmed.2.REF_3 - RE-oxide (RE=Nd, Pr) Quasi-binary EquilibriumREF_3 powder and a RE-oxide pellet were charged in a graphite crucible and heated at 1723 K under argon atmosphere for a scheduled time period. Then, the crucible was pulled out from the furnace and quenched rapidly by jetting helium gas. Two phases, consisting of the melted part and the solid part, were observed in both experiments and the both were subjected to X-my diffraction analysis. The NdOF or PrOF peaks are detected in the both parts.3.RE - REF_3 - RE_20_3 Quasi-ternary SystemAs the REOF phases were identified, new sets of experiments were conducted to determine the RE - REF_3 - REOF quasi-ternary equilibrium. Using those results and the partial phase diagrams of the RE-O system, phase diagrams of the RE - REF_3 - RE_20_3 quasi-ternary system at 1723 K were established. Based on the phase diagrams, deoxidation reactions on the both rare earth metals were estimated.4.Deoxidation ExperimentsThe deoxidation experiments using NdF_3 or PrF_3 as a halide flux were performed in order to confirm the estimated deoxidation reactions. Oxygen content can be successfully lowered by the halide flux treatment. Therefore, the halide flux treatment is not only simple process but also effective deoxidation method.