Fe,Ni置换型方钴矿热电材料高温高压制备及性能研究
发布时间：2018-09-09 14:22
【摘要】：本论文采用高温高压技术制备出单元素、双元素置换到方钴矿Co Sb_3中Co位的热电材料,并对其热电性质进行了研究。重点研究了室温下不同合成压力对方钴矿基热电材料的电学输运性能的影响,并对所合成样品的相结构,微观结构,热电性能进行了测试以及分析。本论文的主要研究内容如下:(1)采用Ni元素进行单一置换,在1-3 GPa条件下成功制备出Ni_xCo_(4-x)Sb_(12)(x=0,0.025.0.1,0.15,0.25)材料。XRD测试结果表明:在合成压力为1GPa时,制备出的样品与标准Co Sb_3谱图匹配良好。SEM电镜照片表明样品的晶粒均匀,晶界明显。此外,样品电学输运性能测试结果表明:在制备压力范围内,样品的Seebeck系数的绝对值与电阻率随着合成压力的增加趋于增加。合成压力为1GPa时,样品Ni_(0.15)Co_(3.85)Sb_(12)具有最优功率因子为9′10-4Wm-1K-2。结果表明:相比纯方钴矿热电材料,通过Ni元素替代到Co Sb_3的Co位后,电学性能得到显著提高。随后对该样品进行中温区热电输运性能相关测试及研究,结果表明:Ni元素替代到样品中可以有效降低样品的总热导率。当合成压力为1GPa时,温度为600K时,样品Ni_(0.15)Co_(3.85)Sb_(12)的最大品质因子ZT值为0.52。(2)采用双元素Fe,Ni置换到Co位,用高温高压方法成功制备出Fe_yNi_(0.15)Co_(3.85-y)Sb_(12)(y=0.2,0.25,0.3)材料。在合成压力范围内,随着合成压力的增加,Seebeck系数的绝对值和电阻率都有所增;1GPa下合成的Fe0.2Ni0.1 5Co3.6 5Sb1 2样品具有室温下的最大功率因子为4.85′10-4Wm-1K-2,随后对该样品进行变温热电输运性能的相关测试,结果表明:Fe,Ni双元素置换到样品中可有效降低样品的晶格热导率,在温度为700K时,最优品质因子ZT值为0.35。综上所述,采用高温高压制备方法,同时通过元素置换到方钴矿的钴位时,能够有效地改善材料的微观结构;优化材料的载流子浓度;造成明显的微观缺陷,以至于促进了声子散射,降低了材料的晶格热导率;最终实现优化材料的热电性能,提高了材料的ZT值。
[Abstract]:In this paper, the thermoelectric materials with single element and double element replacement to Co site in Co Sb_3 were prepared by high temperature and high pressure technique, and their thermoelectric properties were studied. The effect of different synthetic pressures on the electrical transport properties of the pyroelectric materials based on galactic cobalt was studied. The phase structure, microstructure and thermoelectric properties of the synthesized samples were tested and analyzed. The main research contents of this thesis are as follows: (1) Ni_xCo_ (4-x) Sb_ _ (12) (x _ (0) O _ (0) 0. 025.0.1 ~ 0.150.25) Ni_xCo_ (4-x) Sb_ _ (12) material was successfully prepared by single substitution of Ni elements under 1-3 GPa. The results show that: when the synthesis pressure is 1GPa, The prepared samples matched well with the standard Co Sb_3 spectra. The SEM electron microscope photos showed that the grain size of the samples was uniform and the grain boundary was obvious. In addition, the electrical transport properties of the samples show that the absolute value of the Seebeck coefficient and the resistivity of the samples tend to increase with the increase of the synthetic pressure in the range of preparation pressure. When the synthetic pressure is 1GPa, the sample Ni_ (0.15) Co_ (3.85) Sb_ (12) has an optimal power factor of 9 ~ (10 ~ (-4) Wm ~ (-1) K ~ (-2). The results show that the electrical properties of Co Sb_3 are improved significantly after the substitution of Ni element to the Co site of Co Sb_3 compared with pure cobalt ore thermoelectric materials. The thermoelectric transport properties of the sample were measured and studied at moderate temperature. The results show that the substitution of the element of Ni with the sample can effectively reduce the total thermal conductivity of the sample. The maximum quality factor ZT value of Ni_ (0.15) Co_ (3.85) Sb_ (12) was 0.52when the synthesis pressure was 1GPa and the temperature was 600K. (2) Fe_yNi_ (0.15) Co_ (3.85-y) Sb_ (12) (y0.20.250.30) was successfully prepared by high-temperature and high-pressure method. In the range of synthetic pressure, With the increase of synthetic pressure, the absolute value and resistivity of Seebeck coefficient increase. The Fe0.2Ni0.1 5Co3.6 5Sb1 _ 2 sample synthesized at 1 GPA has a maximum power factor of 4.85 脳 10 ~ (-4) W ~ (-1) K ~ (-2) at room temperature. The results show that the lattice thermal conductivity of the samples can be effectively reduced by the substitution of the two elements, and the ZT value of the optimal quality factor is 0.35 at 700K. To sum up, the preparation method of high temperature and high pressure, at the same time, when the elements are replaced to the cobalt site of the galactic ore, can effectively improve the microstructure of the material, optimize the carrier concentration of the material, and cause obvious microscopic defects. Thus the phonon scattering is promoted and the lattice thermal conductivity is reduced. Finally the thermoelectric properties of the material are optimized and the ZT value of the material is improved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34
[Abstract]:In this paper, the thermoelectric materials with single element and double element replacement to Co site in Co Sb_3 were prepared by high temperature and high pressure technique, and their thermoelectric properties were studied. The effect of different synthetic pressures on the electrical transport properties of the pyroelectric materials based on galactic cobalt was studied. The phase structure, microstructure and thermoelectric properties of the synthesized samples were tested and analyzed. The main research contents of this thesis are as follows: (1) Ni_xCo_ (4-x) Sb_ _ (12) (x _ (0) O _ (0) 0. 025.0.1 ~ 0.150.25) Ni_xCo_ (4-x) Sb_ _ (12) material was successfully prepared by single substitution of Ni elements under 1-3 GPa. The results show that: when the synthesis pressure is 1GPa, The prepared samples matched well with the standard Co Sb_3 spectra. The SEM electron microscope photos showed that the grain size of the samples was uniform and the grain boundary was obvious. In addition, the electrical transport properties of the samples show that the absolute value of the Seebeck coefficient and the resistivity of the samples tend to increase with the increase of the synthetic pressure in the range of preparation pressure. When the synthetic pressure is 1GPa, the sample Ni_ (0.15) Co_ (3.85) Sb_ (12) has an optimal power factor of 9 ~ (10 ~ (-4) Wm ~ (-1) K ~ (-2). The results show that the electrical properties of Co Sb_3 are improved significantly after the substitution of Ni element to the Co site of Co Sb_3 compared with pure cobalt ore thermoelectric materials. The thermoelectric transport properties of the sample were measured and studied at moderate temperature. The results show that the substitution of the element of Ni with the sample can effectively reduce the total thermal conductivity of the sample. The maximum quality factor ZT value of Ni_ (0.15) Co_ (3.85) Sb_ (12) was 0.52when the synthesis pressure was 1GPa and the temperature was 600K. (2) Fe_yNi_ (0.15) Co_ (3.85-y) Sb_ (12) (y0.20.250.30) was successfully prepared by high-temperature and high-pressure method. In the range of synthetic pressure, With the increase of synthetic pressure, the absolute value and resistivity of Seebeck coefficient increase. The Fe0.2Ni0.1 5Co3.6 5Sb1 _ 2 sample synthesized at 1 GPA has a maximum power factor of 4.85 脳 10 ~ (-4) W ~ (-1) K ~ (-2) at room temperature. The results show that the lattice thermal conductivity of the samples can be effectively reduced by the substitution of the two elements, and the ZT value of the optimal quality factor is 0.35 at 700K. To sum up, the preparation method of high temperature and high pressure, at the same time, when the elements are replaced to the cobalt site of the galactic ore, can effectively improve the microstructure of the material, optimize the carrier concentration of the material, and cause obvious microscopic defects. Thus the phonon scattering is promoted and the lattice thermal conductivity is reduced. Finally the thermoelectric properties of the material are optimized and the ZT value of the material is improved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34
【参考文献】
相关期刊论文 前4条
1 ;Solvothermal synthesis and thermoelectric properties of skutterudite compound Fe_(0.25)Ni_(0.25)Co_(0.5)Sb_3[J];Rare Metals;2009年03期
2 ;Thermoelectrical properties of(FeNi)_xCo_(4-x)Sb_(12) prepared by MA-SPS[J];Journal of University of Science and Technology Beijing;2008年03期
3 赵雪盈;史迅;陈立东;唐新峰;;Ni掺杂对Co_(4-x)Ni_xSb_(12)热电转换性能的影响[J];无机材料学报;2006年02期
4 朱品文,贾晓鹏,陈海勇,陈立学,李冬妹,郭伟力,马红安,任国仲,邹广田;PbTe的高温高压合成[J];高压物理学报;2002年03期
相关博士学位论文 前4条
1 郭鑫;高性能Bi_2Te_3基材料高温高压制备与热电性能调制[D];吉林大学;2015年
2 李q，
本文编号：2232639
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2232639.html
