Nonstoichiometry and Thermodynamic Properties of Intermetallic compounds

本研究的目的是用电动势法测量具有B_2和AlB_2型结构的金属间化合物的活度，这些化合物具有广泛的非化学计量比组成范围。这些电池是用固体电解质制成的（ZrO_2（+MO），CaF_2）测量电动势; 1：微量添加元素的影响（Sb，Ge，Fe）对CoGa-B2相中镓的活性的影响，2：具有B2型结构的CoAl-NiAl化合物固溶体中Al的活性，3：本文研究了Nd和La在AlB_2颈背结构NdGa_2和LaGa_2金属间化合物中的活度，得到以下结果.在CoGa相的二元系中，证实了我们的原始活度数据。在1173和1273 K时，Sb的加入在整个组成范围内都提高了Ga的活度。1mol%Sb的加入对活性的影响较小，而2mol%和3mol%的Sb的加入对活性有明显的提高作用，且提高程度相差不大。添加Ge（2至6摩尔%）增加 关于我们 在整个组合物范围内减轻了与其量相应的活性。但2%SU在富Ga组份中不起作用。添加Ni（2 ~ 6mol%）可提高富Co区的活性，但随着Ni含量的增加，富Ga区的活性降低。1mol%Fe使富Co区的活性提高，而富Ga区的活性降低。3mol%Fe在整个组成范围内都能提高活性. 1000 K时CoAl-NiAl复合固溶体中Al的活度分别为：（NiAl：5.68×10 ~ 3<-4>），（<42>Ni_Co_8Al：<50>6.78× 10 ~ 3<-5>），（<33>Ni_C_Al_3<17><50>：3.9610 ~ 3<-5>），（<17>Ni_Co_Al_3<33><50>：1.68×10 ~ 3<-5>），（CoAl_3<50>：1.25×10 ~ 3<-5>）。研究发现，随着CoAl浓度的增加，Al的活性降低.用Mn、MnF_2参比电极的CaF_2电动势法，测得NdGa_2（AlB_2型结构）中Nd的活度为：（700 K时x_<Nd>=0.206-0.309 α_<Nd>= 10 ~（10）<-14>× 10 <-11>~（10）<Nd>× 10 <-11>~（10<-8>）），而LaGa_2中La的活度由于电池电动势不稳定而不能精确测定。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