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.

我们完成了对BAO-MGO（ZnO）-TA_2O_5系统在1450℃时的相位关系的调查。 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与钨青铜结构有关。另一个三元相BA10MG0.25TA7.9O30，具有10层六角形钙钛矿结构，只能在1600°平衡后获得。 BA_9MGTA_ <14> O_ <45>相显示量子铁电特性。我们还阐明了与BAO-MGO-TA_2O_5组成字段中与三元和二进制相关的几个矛盾报告。例如，我们没有发现六边形BA_9MG_4TA__ <20> O_ <63>阶段。马里兰州盖瑟斯堡； 2 pp。（2003）]，也无法确认几位作者报告的BA_7TA_6O__ <22>阶段的存在[j。 S. Kim，J.-W。 Kim，C。I. Cheon，Y.-S。 Kim，S。Nahm，J。D. Byun，J。Eur。陶瓷。 Soc。，2001，21，2599;厘米。 Cheng，Y.-T。 Hseih，C.-F。杨，ceram。 Int。，2002，28，255; X. M. Chen，Y。Suzuki，N。Sato，J。Mater。 Sci。：电子产品的材料，1994，5，244]。 TTB类型BA_9MGTA_ <14> O_ <45>沿BATA_2O_6形式。 BA3MGTA2O9加入。我们发现，沿MG_4TA_2O_2O_9-BATA_2O_6 TIE LINE.IN bao-Zno-TA_2O_5系统仅存在BATA_2O_6相的六边形多晶型物。取而代之的是，沿Znta_2O_6-Bata_2O_6 TIE LINE发现了BA_3ZNTA_8O_ <24>阶段。使用单晶体结构分析，我们已经证明了BA_3ZNTA_8O_ <24>相具有同类型，而BA_4MGTA_ <10> O_ <30>相位，并讨论了这些相化学组成差异的原因。