New thermoelectric materials with high performance (ZT>l)-Re silicide 4

高性能新型热电材料（ZT>l）-铼硅化物4

• 批准号: 14350369
• 负责人: INUI Haruyuki
• 金额: $ 10.94万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350369/
• 关键词: Thermoelectric material; Dimensionless figure of merit; Seebeck coefficient; electrical resistivity; Thermal conductivity; Microstructure; Twin; Transmission electron microscopy; 熱電変換材料

There is a renewed interest in thermoelectric materials because of the increased attention to environmental safety. The performance of thermoelectric properties is usually evaluated with the so-called dimensionless figure of merit ZT where Z=α^2σ/κ, and, α, σ, κ denote Seebeck coefficient, electrical conductivity respectively and thermal conductivity. The performance is better for the larger ZT value and it is generally believed that the condition of ZT>1 must be satisfied for thermoelectric materials to be practically used. We have recently found that Re-silicide exhibits a large ZT value close to ZT=1. In the present study, we made an effort to further improve the thermoelectric performance of this Re-silicide through ternary alloying. We expect the performance improvement not only through the changes in electronic structure but also through microstructure changes such as the change in the density and arrangement of Si vacancies and the formation of incommensurate structure. The bina … More ry silicide exhibits ZT=0.75 at 800K when measured along [001]. When transition-metals are replaced with Re, incommensurate microstructures are usually formed starting with the shear structure followed by the adaptive structure as the alloying content increases. The alloying amount at which the transition from the shear to adaptive structures occurs depend on each alloying elements. This occurs at a low content for Mo and W while the adaptive structure does not form within the solubility limit for Ru, Fe, Cr and Nb. Generally speaking, the property improvement occurs when the alloy takes the adaptive-type structure, whereas when the alloy takes the shear-type structure, no significant improvement occurs. The ZT value of 0.85 is achieved for 2at.% Mo added Re-silicide, which exhibits an adaptive structure. When Al is added to replace Si, the adaptive structure is locally formed in the close vicinity of twin boundaries. This leads to the significantly decreased thermal conductivity, resulting in the Zt value greater than 1 at 400K. Less

由于对环境安全的日益关注，人们对热电材料重新产生了兴趣。通常用所谓的无量纲优值系数ZT来评价热电性能，其中Z=α^2σ/κ，α，σ，κ分别表示塞贝克系数、电导率和热导率。热电材料的ZT值越大，其性能越好，一般认为热电材料必须满足ZT&GT；1的条件才能得到实际应用。最近我们发现Re硅化物具有接近ZT=1的大的ZT值。在本研究中，我们努力通过三元合金化来进一步提高这种Re硅化物的热电性能。我们期望性能的改善不仅通过电子结构的变化，而且还通过微观结构的变化，如改变Si空位的密度和排列以及形成无公度结构。比娜·…更多的RY硅化物在800K时显示出ZT=0.75，当沿[001]测量时。当用Re取代过渡金属时，随着合金化含量的增加，通常从剪切组织开始形成无公度组织，然后是适应组织。从剪切组织向自适应组织转变的合金化量取决于每种合金元素。这发生在Mo和W含量较低时，而Ru、Fe、Cr和Nb则没有在固溶度极限内形成自适应结构。一般而言，合金采用适配型组织时，性能有所改善，而当合金采用剪切型组织时，性能改善不明显。添加2at.%Mo的再硅化物的ZT值为0.85，表现出自适应的结构。当添加Al替代Si时，自适应结构在孪晶界附近局部形成。这导致导热系数显著降低，导致在400K时ZT值大于1。较少

项目成果

H.Inui: "Crystal Structure and Thermoelectric Properties of ReSi_<1.75> Silicide"Materials Research Society Symposium Proceedings. (印刷中). (2003)

H.Inui：“ReSi_<1.75>硅化物的晶体结构和热电性能”材料研究会研讨会论文集（2003 年出版）。

H.Inui et al.: "Properties and Microstructures of a High-Performance Thermoelectric Intermetallic Compounds -β-Zn_4Sb_3"Materials Science Forum. 426-432. 75-81 (2003)

H.Inui 等人：“高性能热电金属间化合物 -β-Zn_4Sb_3 的性能和微观结构”材料科学论坛 426-432 (2003)。

H.Inui et al.: "Thermoelectric Properties of ReSi_<1.75> Based Silicides -Property Improvements through Defect Engineering"Proc.12th Int.Symp.on Processing and Fabrication of Advanced Materials (ASM). (in press). (2004)

H.Inui等人：“ReSi_<1.75>基硅化物的热电性能-通过缺陷工程改进性能”Proc.12th Int.Symp.on Advanced Materials (ASM)加工和制造。

H.Inui: "Reduction of the C49→C54 Phase Transformation Temperature in Co-Sputtered TiSi_2 Thin Films by Ternary Alloying"Intermetallics. 11・5. 417-424 (2003)

H.Inui：“通过三元合金化降低共溅射 TiSi_2 薄膜中的 C49→C54 相变温度”11・5 (2003)。

H.Inui: "Thermoelectric Properties of ReSi_<1.75> Based Silicides - Property Improvements through Defect Engineering"Proc. 12^<th> Int.Symp. on Processing and Fabrication of Advanced Materials. (印刷中). (2004)

H.Inui：“基于 ReSi_<1.75> 的硅化物的热电性能 - 通过缺陷工程改进性能”Proc. 12^<th> Int.Symp，关于先进材料的加工和制造（2004 年）。