| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
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
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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
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