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本文用X射线衍射和差热分析方法对La-Ga二元系相图的富Ga部份进行了研究。发现在La-Ga系相图的富Ga部份存在着一包晶反应,形成一新的金属互化物,其均匀范围很窄。确定了这一新化合物为LaGa_6,属四方晶系,空间群为P4/nbm,点阵常数α=6.1041,c=7.7052且。另外还发现LaGa_2这一金属互化物存在着一个相区,其均匀范围为66.7A/0Ga到71.6A/0 Ga。在这一相区内,点阵常数α随Ga含量的递增而增大,c随之减少。论证了这一固溶体系由一对Ga原子无序地替代一个La原子的结果。
In this paper, the Ga-rich part of the La-Ga binary system phase diagram has been studied by X-ray diffraction and differential thermal analysis. It is found that there exists a peritectic reaction in the Ga-rich part of the La-Ga phase diagram, forming a new intermetallic compound with a narrow uniform range. The new compound is identified as LaGa_6, belongs to the tetragonal system, space group is P4 / nbm, lattice constant α = 6.1041, c = 7.7052 and. In addition, it is also found that there is a phase region in LaGa_2 intermetallic compound with an average range of 66.7A / 0Ga to 71.6A / 0Ga. In this phase region, lattice constant α increases with increasing Ga content, and c decreases. The result shows that this solid solution system is composed of a pair of Ga atoms randomly substituted for one La atom.