Development of the BaO-Mg(Zn) O-Ta_2O_5 ternary phase diagram for single crystal growth of the Ba(Mg_<1/3> Ta_<2/3>) O_3 and Ba(Zn_<1/3> Ta_<2/3>) O_3 using off-stoichiometric composition method

Ba(Mg_<1/3> Ta_<2/3>) O_3和Ba(Zn_<1/3> Ta_<2/单晶生长的BaO-Mg(Zn) O-Ta_2O_5三元相图的建立

基本信息

批准号：
21560025
负责人：
KOLODIAZHNYI Taras
金额：
$ 1.91万
依托单位：
National Institute for Materials Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2011
项目状态：
已结题

项目摘要

We completed investigation of the phase relation in the BaO-MgO(ZnO)-Ta_2O_5 system equilibrated at 1450℃. In the BaO-MgO-Ta2O5 system we found three ternary phases, namely 3:1:1 perovskite Ba_3MgTa_2O_9, 9:1:7 TTB(tetragonal tungsten bronze)-type Ba_9MgTa_<14> O_<45> and 4:1:5 Ba_4MgTa_<10> O_<30> with close relation to the tungsten bronze structure. Another ternary phase, Ba10Mg0.25Ta7.9O30, with 10 layer hexagonal perovskite structure can be only obtained after equilibration at 1600℃. The Ba_9MgTa_<14> O_<45> phase shows quantum ferroelectric properties.We have also clarified several contradictory reports related to the ternary and binary phases in the BaO-MgO-Ta_2O_5 composition field. For example, we found no evidence of the hexagonal Ba_9Mg_4Ta_<20> O_<63> phase that was claimed by R. S. Roth[` Phase Equilibria of Experimental Ceramic Systems', NIST Project Report, Report No.1, Contract No.SB1341-02-W-0787, National Institute of Standards and Technology, Ceramics Division ; Gaithersburg, Maryland ; 2 pp.(2003)], nor we can confirm the existence of the Ba_7Ta_6O_<22> phase reported by several authors[J. S. Kim, J.-W. Kim, C. I. Cheon, Y.-S. Kim, S. Nahm, J. D. Byun, J. Eur. Ceram. Soc., 2001, 21, 2599 ; C.-M. Cheng, Y.-T. Hseih, C.-F. Yang, Ceram. Int., 2002, 28, 255 ; X. M. Chen, Y. Suzuki, N. Sato, J. Mater. Sci.: Materials in Electronics, 1994, 5, 244]. The TTB type Ba_9MgTa_<14> O_<45> forms along the BaTa_2O_6. Ba3MgTa2O9 join. We found that only hexagonal polymorph of the BaTa_2O_6 phase exists along the Mg_4Ta_2O_9-BaTa_2O_6 tie line.In the BaO-ZnO-Ta_2O_5 system we could not confirm the existence of the Ba_4ZnTa_<10> O_<30> compound. Instead, a Ba_3ZnTa_8O_<24> phase has been found along the ZnTa_2O_6-BaTa_2O_6 tie line. Using single crystal structural analysis we have demonstrated that the Ba_3ZnTa_8O_<24> phase is isotypical with the Ba_4MgTa_<10> O_<30> phase and discussed the reasons for the difference in the chemical composition of these phases.

我们完成了在1450℃平衡的BaO-MgO(ZnO)-Ta_2O_5体系中的相关系的研究在BaO-MgO-Ta2O5体系中我们发现了三个三元相，即3:1:1钙钛矿Ba_3MgTa_2O_9、9:1： 7 TTB(四方钨青铜)型Ba_9MgTa_<14> O_<45>和4:1:5 Ba_4MgTa_<10> O_<30>与钨青铜结构密切相关，只有在10℃平衡后才能得到具有10层六方钙钛矿结构的三元相Ba10Mg0.25Ta7.9O30。 1600℃时Ba_9MgTa_<14>O_<45>相呈现量子态。我们还澄清了BaO-MgO-Ta_2O_5成分领域中有关三元相和二元相的一些相互矛盾的报道，例如，我们没有发现Ba_9Mg_4Ta_<20>O_<63>相的证据。 R. S. Roth[“实验陶瓷系统的相平衡”，NIST 项目报告，第 1 号报告，合同No.SB1341-02-W-0787，国家标准与技术研究所，马里兰州盖瑟斯堡；2 页（2003）]，我们也无法证实几位作者报道的 Ba_7Ta_6O_<22> 相的存在[ J. S. Kim、J.-W. Kim、C. I. Cheon、Y.-S Kim、S. Nahm、J. D. Byun、J. Eur.Soc.，2001，Y.-T.Yang，Ceram，2002，28，255；铃木，N.佐藤，《材料科学》：电子材料，1994，5， 244]。TTB型Ba_9MgTa_<14>O_<45>沿着BaTa_2O_6连接我们发现沿着Mg_4Ta_2O_9-BaTa_2O_6连接线仅存在BaTa_2O_6相的六方多晶型。无法确认其存在相反，沿着 ZnTa_2O_6-BaTa_2O_6 连接线发现了 Ba_3ZnTa_<10> O_<30> 相，我们证明 Ba_3ZnTa_8O_<24> 相与 Ba_4MgTa_< 是同型的。 10>O_<30>相并讨论了差异的原因这些相的化学成分。