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Design for Ultra Low Thermal Expansion Properties of Cubic Cs-leucite Compounds

立方铯白榴石化合物超低热膨胀性能的设计

基本信息

批准号：
12650666
负责人：
KOBAYASHI Hidehiko
金额：
$ 1.73万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

We chose a cubic pollucite, CsAlSi_2O_6, as a template compound, and report that the cubic Cs-leucite compounds with various chemical compositions can be synthesized by multi-step heating process as a solid-state reaction method, and that the thermal expansion properties in the range 298-1273K for all of the synthesized compounds were examined by using low- and high-temperature XRD.The results obtained can be summarized as follows.1. Cubic Cs-leucite compounds ; Cs-leucites : CsMSi_2O_6(M=B,Al,Fe,B_<0.2>Al_<0.8>,Al_<0.5>Fe_<0.5>,Al_<0.2>Fe_<0.8>), Cs_2MSi_5O_<12>(M=Cd,Fe,Mg,Ni,Zn), Cs-Na-leucites : Cs_<1-X>Na_XASI_2O_6(X=0.1,0.2), Cs_<0.9-XNa_X>Al_<0.9>Si_<2.1>O_6(X=0.1,0.2), and RbAlSi_2O_6, can be successfully synthesized by the multi-step heat treatment.Their crystal structures, as determined by XRD analysis, were found to belong to space group Ia-3d of the cubic crystal system in the range 298-1273K.2. The thermal expansion rates of the synthesized cubic Cs-leucite compounds were clearly varied with the chemical composition of Cs-leucite compounds. In addition, the effect of the substitution of alkaline metalion of which ionic radius was smaller than Cs^+ ion led to the enhanced low thermal expansion rates of the cubic Cs-lecuite compounds.3. The thermal expansion rates of the cubic Cs-leucite compounds ; Cs-leucites, Cs-Na-leucites and Cs-Li-leucites were changed by not only the amount of Cs^+ ions but also the space ratio owing to the difference of the cation size between Cs^+ ions and Na^+ or Li^+ ions.4. The Windows95/98/NT application softwares can use the CIF as the crystal structure data was developed to simplify a display of complex crystal structure such as silicate compounds using the coordination polyhedron.5. The thermal expansion rates of the synthesized cubic Cs_<0.8>Li_<0.1Al_<0.9>Si_<2.1>O_6 and Cs_<0.7>Li_<0.2>Al_<0.9>Si_<2.1>O_6were 0.11% at 1173K and 0.081 % at 1073K, which were lower than that of Cs_<0.9>Al_<0.9>Si_<2.1>O_6, 0.2 % at 1273K.

本文以立方铯榴石CsAlSi_2O_6为模板化合物，采用多步加热固相反应法合成了不同化学组成的立方铯榴石化合物，并通过使用低-和高-热膨胀系数测试了所有合成化合物在298- 1273 K范围内的热膨胀性能。所获得的结果可以总结如下。1.立方Cs-白榴石化合物; Cs-白榴石：CsMSi_2O_6（M=B，Al，Fe，B_<0.2>Al_<0.8>，Al_<0.5>Fe_<0.5>，Al_<0.2>Fe_<0.8>），Cs_2MSi_5O_<12>（M=Cd，Fe，Mg，Ni，Zn），Cs-Na-白榴石：<1-X>Cs_Na_XASI_2O_6（X = 0.1，0.2），<0.9-XNa_X>Cs_Al_Si_O_6<0.9><2.1>（X = 0.1，0.2）和RbAlSi_2O_6的晶体结构。在298- 1273 K范围内属于立方晶系的Ia-3d空间群。合成的立方Cs-白榴石化合物的热膨胀率明显地随Cs-白榴石化合物的化学组成而变化。此外，离子半径小于Cs^+离子的碱金属离子的取代效应导致了立方Cs-白榴石化合物的低热膨胀率的提高.由于Cs ^+离子与Na^+或Li^+离子的阳离子尺寸不同，Cs-白榴石、Cs-Na-白榴石和Cs-Li-白榴石的热膨胀率不仅与Cs^+离子的量有关，而且与空间比有关. Windows95/98/NT应用软件可以使用CIF作为晶体结构数据，简化了用配位多面体显示硅酸盐化合物等复杂晶体结构的工作.合成的立方相Cs_<0.8>Li_0.1Al_<0.9>Si_<2.1>O_6和Cs_<0.7>Li_<0.2>Al_<0.9>Si_O_6的热膨胀率分别<2.1>为0.11%和0.081%，低于Cs_<0.9>Al_<0.9>Si_<2.1>O_6在1273 K时的0.2%。