Nonstoichiometry and Thermodynamic Properties of Intermetallic compounds

本文研究了用电动势法测定非化学计量组成范围广的B2型和al_2型结构金属间化合物的活性。采用固体电解质（ZrO_2（+MO）和CaF_2）构建电池，测量电动势，研究了微量附加元素（Sb、Ge、Fe）对CoGa-B2相中镓活性的影响，B2型结构煤- nial复合固溶体中Al活性的影响，以及AlB_2尾状结构NdGa_2和LaGa_2金属间化合物Nd和La活性的影响。得到了以下结果：在CoGa相二元体系中，我们的原始活度数据得到了证实。在1173和1273K的整个组成范围内，添加Sb提高了Ga的活性。添加1mol% Sb对活性的影响较小，而添加2mol % Sb和3mol % Sb对活性的增加效果较好，且增加幅度相差不大。在整个组成范围内，添加Ge （2 ~ 6mol %）对活性的影响与添加量相对应。但2%的su在富Ga成分中不起作用。随着Ni含量的增加，富co区活性增加，富ga区活性降低。1mol % Fe增加富co区活性，降低富ga区活性。在整个组成范围内，3mol % Fe的活性增加。活动的基地在1000 K的复合固溶CoAl-NiAl是:(NiAl: 5.68×10 ^ < 4 >),(Ni_ < 42 > Co_8Al_ < 50 >: 6.78×10 ^ < 5 >),(Ni_ < 33 > C_ < 17 > Al_ < 50 >: 3.9610 ^ < 5 >), (Ni_ < 17 > Co_ < 33 > Al_ < 50 >: 1.68×10 ^ < 5 >),(CoAl_ < 50 >: 1.25×10 ^ < 5 >)。结果表明，随着煤浓度的增加，铝的活性逐渐降低。以Mn、MnF_2为基准电极，用CaF_2电动势法测定了NdGa_2 （AlB_2型结构）中Nd的活度为：在700K时x_<Nd>=0.206 ~ 0.309 α_<Nd>= 10^<-14> ~ 10^<-11>，在900 K时α_<Nd>= 10^<-11> ~ 10^<-8>，但由于电池的电动势不稳定，无法精确测定La在LaGa2中的活度。少

The aim of this study is to measure the activity in the intermetallic compounds with B2 and AlB_2 type structures which have wide composition range of non-stoichiometry by EMF methods. The cells are constructed with solid electrolytes (ZrO_2(+MO), and CaF_2) to measure the EMF and 1: the effect of amall amount of additional elements (Sb,Ge,Fe) on the activity of gallium in the CoGa-B2 phase, 2: activity of Al in CoAl-NiAl compound solid solution with B2 type structure, 3: activity of Nd and La in the intermetallic compounds of NdGa_2 and LaGa_2 with AlB_2 nape structure are studied.The following results are obtained.1. In the binary system of CoGa phase, original data of activity by us are confirmed. Addition of Sb increases the activity of Ga in the whole composition range at 1173 and 1273K. The effect of 1mol% Sb addition is small, but 2 and 3 mol% addition increase the activity effectively and the difference of the degree of increments is similar. Addition of Ge ( 2 to 6 mole%) incr … More eases the activity corresponding to its amount in the whole composition range. But 2%SU is not effective in the Ga rich composition. Addition of Ni (2 to 6 mole%) increases the activity in Co-rich region but decreases in the Ga-rich region with increasing Ni content. 1mole% Fe increases the activity in Co-rich region but decreases in the Ga-rich region. 3mole% Fe increases the activity in the whole composition range.2. Activity of Al at 1000 K in the compound solid solution of CoAl-NiAl is : (NiAl : 5.68×10^<-4>),(Ni_<42>Co_8Al_<50> : 6.78× 10^<-5>), (Ni_<33>C_<17>Al_<50> : 3.9610^<-5>), (Ni_<17>Co_<33>Al_<50> : 1.68×10^<-5>), (CoAl_<50> : 1.25×10^<-5>). It is found that the activity of Al decreases with the increasing of the CoAl concentration.3. By use of CaF_2 EMF method with Mn,MnF_2 reference electrode, activity of Nd in NdGa_2 (AlB_2 type structure) is determined to be : (x_<Nd>=0.206-0.309 α_<Nd>= 10^<-14> 〜10^<-11> at 700K and α_<Nd>= 10^<-11>〜10^<-8> at 900 K), but activity of La in LaGa2 could not be determined precisely because the EMF of the cell was not stable. Less