IONIC CONDUCTION IN NEW COMPOUNDS OF THE TERNARY SYSTEMS

首先，我们研究了CaSO_4-CaCl_2和SrSO_4-SrCl_2体系中的样品，以及CaCO_3-CaCl_2和SrCO_3-SrCl_2体系中的样品。在各体系中，当添加剂含量在10 ~ 30 mol%之间时，均可形成固溶体，即SO_4^<2->或CO_3^<2->可被氯离子取代。而且，尽管基材在所有情况下都表现出非常低的电导率，但随着添加剂成分的增加，取代样品的电导率提高了。这些样品中的载流子被发现只是离子，而不是电子。为了使CO_2传感器在含有高浓度CO_2气体的环境中保持稳定，我们对碳酸盐组成的材料进行了研究。从细胞的EMF响应判断，这些材料被发现是它的候选者。其次，为了研究以白钨矿和尖晶石型化合物为基料的固溶体中氧化物离子的电导率，我们合成了Pb_<1-x>Ln_xWO_<4+X/2>、Pb_<1-x>Ln_ <2x/3>WO_4和Zn_<2- X/2> Ti_<1-x>Ta_xO_4固溶体，并测量了它们的电导率。结果表明，在800℃时，前两种体系的氧化离子电导率均高于10^<-2> Scm^<-1>。在后一种情况下，没有观察到如此高的电导率，但发现在最接近的氧化物离子堆积结构中，氧化物离子的电导率是可能的。即使在白钨矿型结构中，如果将取代态设计为Ca_<1-x>Li_<2x>WO_4，也可以观察到阳离子（锂离子）的导电。在这种情况下，根据NRG的观察结果，认为锂离子的传导是由间隙锂离子引起的。

At first, we have investigated on the samples in the systems CaSO_4-CaCl_2 and SrSO_4-SrCl_2, and CaCO_3-CaCl_2 and SrCO_3-SrCl_2. In each system, if the additives content was between 10-30 mol%, the solid solutions were found to be formed, which means that SO_4^<2-> or CO_3^<2-> can be substituted by the chloride ions. And, although the based materials showed very low conductivity in all cases, the conductivity in the substituted samples grew higher with increasing additive components. The charge carrieres in these samples were found to be only ions, not electrons. Here, we paid attention to the materials composed of carbonate in order to make a CO_2 sensor stable in the environment containing fairly high concentration of CO_2 gas. Judging from the EMF response of the cell, these materials were found to be a candidate for it.Next, in order to study the oxide ion conduction in the solid solutions based on Scheelite- and Spinel-type compounds, which have not been investigated at all as to their ionic conduction, we synthesized the solid solutions of Pb_<1-x>Ln_xWO_<4+X/2>, Pb_<1-X>Ln_<2x/3>WO_4 and Zn_<2-x/2>Ti_<1-x>Ta_xO_4, and measured their conductivities. As a result, in the former two systems, the high oxide ion conduction was observed, the value of which exceeded 10^<-2> Scm^<-1> at 800ﾟC.In the latter case, such a high conductivity was not observed but the oxide ion conduction was found to be possible in the closest packing structure of oxide ions. Even in the case of the Scheelite-type structure, the cation (lithium ion) conduction was found to be observed, if we designed the substitution as Ca_<1-x>Li_<2x>WO_4. In this case, the lithium ion conduction was considered to be ascribed by the interstitial lithium ions by the result of the observation of NRG.