共查询到17条相似文献,搜索用时 62 毫秒
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负热膨胀材料在诸多工业领域拥有广阔应用价值,在此类材料中,锰基反钙钛矿化合物近年来被广泛研究。本工作对具有负膨胀效应的Mn3AN(C)(A=主族或过渡族元素)化合物进行了综述与评论。讨论了该化合物特殊热膨胀行为及与磁结构和磁相转变的关系,指出其特殊磁结构是Mn3AN(C)化合物中产生磁容积效应的重要因素,Fermi能级处的电子态密度与磁相转变具有强关联性。由负热膨胀材料Mn3AN与金属铜组成的金属基复合材料显示有低热膨胀和近零热膨胀行为,可通过改变Mn3Cu0.5A0.5N(A=Ni,Sn)的混合含量,调控金属铜的热膨胀系数。 相似文献
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通过变温X射线衍射技术研究了反钙钛结构Mn3XN(X=Ga,Zn,Sn,Cu)化合物的热膨胀性质.随着温度的升高,此类材料在磁相变附近有时会伴随人的品格收缩,即负热膨胀效应.尽管如此,晶格收缩并不总是发生,如:Mn3ZnN,Mn3CuN,Mn3SnN.对这种独特的热膨胀性质与X位 置元素价电子数之间的关系进行了讨论.结果表明:3价元素更有利于此类化合物产生负热膨胀效应.通过X位置无素掺杂,可调控此类材料的负热膨胀系数和温区.Mn3Zn0.5Ge0.5N的负热膨胀系数可达-7.15×10-6/K,温区扩展到100K左右.此外,还发现Mn3GaN和Mn3Zn0.7Sn0.3N在室温附近, 晶胞常数随温度的升高几乎保持不变,显示为近零膨胀. 相似文献
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近零热膨胀材料在变温环境下具有高的尺寸稳定性,不易产生热应力,可保证相关器件或构件具有高的精密性和稳定的使用寿命,因此其在航空航天、微电子、光学、精密仪器仪表等领域具有重要应用价值。锰基反钙钛矿化合物Mn3AX(A=金属或半导体元素,X=N或C)由于具有宽温区、各向同性、易调控的负或近零热膨胀性质,近年来引起广泛关注。Mn3AX化合物具有丰富的磁结构,此类化合物负或近零热膨胀性质与其磁相变和晶格-自旋强关联特性密切相关。因此,通过优化组分可改变其磁结构及磁相变过程,进而有效调控其热膨胀行为并获得其它功能物性。综述并评价了国内外研究者在Mn3AX反常热膨胀行为调控方面所做的实验和理论工作。对锰基反钙钛矿化合物反常负/零热膨胀性质实验上的有效调控和机制上的深入分析,对揭示反常热膨胀的物理起源具有重要意义,能够积极推动这类材料走向应用。旨在总结目前本领域的研究进展,着重介绍了锰基反钙钛矿化合物负/零热膨胀性质的调控策略与机理研究,也对本领域未来的研究趋势进行了展望。 相似文献
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复合氧化物材料的负热膨胀机理 总被引:4,自引:0,他引:4
介绍了相转变、桥氧原子的横向热振动、刚性多面体的旋转耦合、固体内压转变、相界面弯曲、阳离子迁移等六种模式的负热膨胀机理。并对其应用前景和发展趋势进行了预测 相似文献
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ZrW2O8是由0.3K至分解温度1050K都具有各向同性的负热膨胀化合物,但由于其窄的热稳定范围反应合成相当困难。本文综述了该材料的各种合成技术以及该材料的负热膨胀的机理,讨论了ZrW2O8的特性,介绍了其潜在的应用。 相似文献
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以分析纯In2O3和WO3为原料,采用固相反应法制备In2W3O12陶瓷。利用X射线衍射仪、场发射扫描电子显微镜、热重分析仪、差示扫描量热仪和热机械分析仪对样品的物相组成、微观结构、相变和热膨胀特性进行了表征。结果表明:在900℃烧结6h可制备出纯的单斜相In2W3O12陶瓷,In2W3O12陶瓷断面晶粒均匀,平均尺寸为4~6μm。In2W3O12陶瓷在253.34℃发生单斜相到斜方相的相转变,单斜相的In2W3O12陶瓷显示正热膨胀,在27~249℃,其平均热膨胀系数为16.51×10-6℃-1,斜方相的In2W3O12陶瓷显示负热膨胀,在273~700℃,其平均热膨胀系数为-3.00×10-6℃-1。 相似文献
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以分析纯Er2O3和WO3为原料,采用固相法制备Er2W3O12陶瓷,并利用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)和热重分析仪(TG)对其结构组分、断面形貌和吸湿特性进行表征.采用热膨胀仪和变温XRD对Er2W3O12陶瓷的负热膨胀特性进行表征.结果表明:在950 ℃烧结6 h制得的Er2W3O12陶瓷结构致密.Er2W3O12材料在室温下容易吸湿,在120 ℃完全失去吸湿水,表现为正交相的Er2W3O12陶瓷,具有良好的负热膨胀性能,其在138~700 ℃的平均热膨胀系数为-7.94×10-6 K-1.变温XRD分析发现:Er2W3O12陶瓷沿三个晶轴方向均表现为负热膨胀,在100~600 ℃温度区间内,Er2W3O12陶瓷的热膨胀系数为-7.81×10-6 K-1. 相似文献
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Huiqing Lu Ying Sun Kewen Shi Lili Wu Ben Niu Cong Wang 《Journal of the American Ceramic Society》2023,106(6):3792-3799
We synthesized antiperovskite Mn3Ga1−xFexN (0 ≤ x ≤ 0.30) compounds and investigated their negative thermal expansion (NTE) behavior, structure, and magnetic properties. A high-resolution transmission electron microscopy analysis and a selected-area electron diffraction (SAED) pattern indicate that the samples have high crystallinity with a single-phase cubic structure. Tunable NTE behavior appears below room temperature, and the NTE operation temperature range (△T) is broadened while increasing the Fe doping. Furthermore, introducing Fe in Mn3Ga1−xFexN can efficiently adjust the NTE coefficient from −232.57 × 10−6/K (x = 0) to −12.57 × 10−6/K (x = 0.20), and the corresponding △T can be broadened from △T = 22 K to 51 K. Besides, the total entropy change (ΔStotal) at the phase transitions continuously decreases from 9.2 to 4.7 J/(kg K) while increasing the Fe content from x = 0.05 to 0.10. With increasing Fe into Ga sites, the magnetic ordering varies from antiferromagnetic (AFM) to ferromagnetic (FM), the AFM to paramagnetic (PM) phase transition temperature decreases, whereas the FM to PM transition temperature increases when increasing the Fe content. The present study indicates that magnetic element doping can efficiently tune the NTE and the correlated physical features of the antiperovskite compounds. 相似文献
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Tunable negative thermal expansion and structural evolution in antiperovskite Mn3Ga1−xGexN (0 ≤ x ≤ 1.0) 下载免费PDF全文
Huiqing Lu Ying Sun Sihao Deng Kewen Shi Lei Wang Wenjun Zhao Huimin Han Shenghua Deng Cong Wang 《Journal of the American Ceramic Society》2017,100(12):5739-5745
The negative thermal expansion (NTE) and structural evolution of antiperovskite compounds Mn3Ga1?xGexN (0 ≤ x ≤ 1.0) were systematically investigated. Our results indicate the crystal structure of Mn3Ga1?xGexN changes from cubic (C) to tetragonal (T4) with increasing Ge content by X‐ray diffraction (XRD).The negative thermal expansion from x = 0 (operation‐temperature range ?T = 20 K) to x = 0.4 (?T = 60 K) becomes broad and shifts to higher temperature, and then it became positive from x = 0.5 in Mn3Ga1?xGexN. Typically, Mn3Ga0.5Ge0.5N shows low thermal expansion behavior between 300 and 450 K (?T = 150 K), and thermal expansion coefficient α is estimated to be 2 × 10?6 K?1. Furthermore, variable temperature XRD was measured to reveal the origin of NTE. The cubic I ‐ cubic II phases coexistence (x = 0.2) and cubic I ‐ tetragonal coexistence (x = 0.5, 0.6) was observed at low temperature. The tunable NTE is highly valuable for practical applications in precision devices. 相似文献
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以分析纯Y2O3、La2O3和MoO3为原料,采用固相反应法制备Y2–xLaxMo3O12(0≤x≤2.00)系列陶瓷。利用X射线衍射仪、场发射扫描电子显微镜、能谱仪、热重分析仪和热机械分析仪对样品的物相组成、微观结构、吸湿性和热膨胀特性进行了表征。结果表明:在750℃烧结10 h可制备得到Y2–xLaxMo3O12(0≤x≤2.00)系列陶瓷;Y2–xLaxMo3O12(0≤x≤2.00)陶瓷断面晶粒呈不规则多边形,为多孔结构。热重分析发现:Y2Mo3O12陶瓷易吸湿,掺入La后吸湿现象消失。在178~600℃测试温度范围内,随La掺入量增加,Y2–xLaxMo3O12(0≤x≤2.00)系列陶瓷样品的热膨胀系数呈增大趋势。 相似文献
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Synthesis of NaTi2(PO4)3 by the Inorganic–Organic Steric Entrapment Method and Its Thermal Expansion Behavior 下载免费PDF全文
Waltraud M. Kriven 《Journal of the American Ceramic Society》2016,99(11):3586-3593
Crystalline pure NaTi2(PO4)3 (NTP) powder was synthesized at 700°C using a simple and low energy, hybrid inorganic–organic, steric entrapment method. Sodium nitrite (NaNO2) and ammonium phosphate dibasic ((NH4)2HPO4) dissolved in water, whereas titanium (IV) isopropoxide (Ti[OCH(CH3)2]4) hydrolyzed in water. Ethylene glycol (HOCH2CH2OH) was used as a polymeric entrapper and hydrolysis of the Ti source was hindered by its dissolution in isopropyl alcohol. The resulting NTP powder was characterized by thermogravimetric analysis/differential thermal analysis, X‐ray diffractometry, scanning electron microscopy, specific surface area by Brunauer–Emmett–Teller nitrogen absorption, and particle size analysis. Furthermore, C, H, N were measured by the classical Pregl‐Dumas method. The thermal expansion behavior in all {hkl} pole directions was also determined by in situ high‐temperature X‐ray diffraction using synchrotron radiation and was found to be in agreement with other published studies. 相似文献