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本文用X射线多晶衍射方法和差热分析方法研究了LaNi_(5-x)Si_x(x≤1.25)的相关系,用排水取气法测量了样品的吸H_2性能,LaNi_5,的固溶体和新的三元化合物LaNi_4Si形成共晶体系,共晶温度1170℃,共晶点x=0.96,在单相区中LaNi_5,相点阵常数随Si替代量增加,a减小,c增大,三元化合物LaNi_4Si属正交晶系,点阵常数a=8.382,b=5.210,c=3.989。测量密度D_0=7.59g/cm~3,每单胞含两个化合式单位,可能的空间群为D_(2h)~5,C_(2v_~2和C_(2v)~4,它具有可逆的吸放H_2性能,吸H_2后形成氢化物LaNi_4SiH_3.6。La_(l-y)Si_yNi,系列样品吸H_2量随Si含量增加而很快下降,LaNi_(5-x)Si_x系列样品吸H_2量随Si含量的增加稍略下降,平台压力也下降,LaNi_(4.8)Si_(0.2)的生成自由能为476cal/mol H_2,固溶体氢化物的稳定性比LaNi_1高。
In this paper, the phase relationship between LaNi_ (5-x) Si_x (x≤1.25) and polycrystalline X-ray diffraction (XRD) The eutectic temperature of LaNi_4Si is 1170 ℃, and the eutectic point is 0.96. The LaNi_5 phase lattice constant increases with Si substitution amount, a decreases and c increases in the single phase region. The ternary The compound LaNi_4Si belongs to the orthorhombic system. The lattice constant a = 8.382, b = 5.210, c = 3.989. The measured density D_0 = 7.59g / cm ~ 3, containing two compound units per unit, the possible space group is D_ (2h) ~ 5, C_ (2v_ ~ 2 and C_ (2v) ~ 4) H 2 absorption and desorption, H 2 H 2 formed after the hydride LaNi 4 SiH 3 6.La ly Si iy, the amount of H 2 absorbed by the sample decreased rapidly with the increase of Si content. The amount of H 2 O absorbed by the LaNi 5-x Si x sample increased with the Si content Slightly lower than that of LaNi_1, the pressure of platform decreases, the free energy of formation of LaNi_ (4.8) Si_ (0.2) is 476cal / mol H_2, and the stability of solid solution hydride is higher than that of LaNi_1.