Solvothermal synthesis and thermoelectric properties of skutterudite compound Fe（0.25）Ni（0.25）Co（0.5）Sb3

Nanostructured skutterudite-related compound Fe_0.25Ni_0.25Co_0.5Sb₃ was synthesized by a solvothermal method using FeCl₃, NiCl₂, CoCl₂, and SbCl₃ as the precursors and NaBH₄ as the reductant. The solvothermally synthesized powders consisted of fine granules with an average particle size of tens of nanometers. The bulk material was prepared by hot pressing the powders. Transport property measurements indicated a heavily doped semiconductor behavior with n-type conduction. The thermal conductivity is about 1.83 W·m⁻¹·K⁻¹ at room temperature and decreases to 1.57 W·m⁻¹·K⁻¹ at 673 K. The low thermal conductivity is attributed to small grain size and high porosity. A maximum dimensionless figure of merit of 0.15 is obtained at 673 K.     

溶剂热法制备纳米Pb（Zr0．52Ti0．48）O3粉体

以硝酸铅、氧氯化锆、四氯化钛、氢氧化钾和氨水为原料，以乙醇和水的混合液为溶剂，采用溶剂热法合成了纳米Pb（Zr0．52Ti0．48）O3粉体。通过XRD和TEM对粉体进行了表征，并研究了醇水比（Vethanol/Vwater）和温度对粉体物相和粒径的影响。研究结果表明：在180℃、醇水比1：1以及KOH为2mol／L的条件下，可以制备粒径约为10nm的PZT粉体；适量乙醇的加入有利于合成纳米PZT粉体并降低生成PZT所需的温度。     

L-半胱氨酸辅助溶剂热法合成CZTS微球（英文）

通过简单的L-半胱氨酸辅助溶剂热法成功制备了Cu_2ZnSnS_4(CZTS)纳米晶。实验使用CuCl_2,SnCl_2·H_2O,ZnCl_2.2H_2O作金属前体,L-半胱氨酸作硫源和模板剂。并对不同温度对产物的大小和形貌进行研究。所得的样品使用X-射线衍射仪(XRD),场发射扫描电镜(FESEM),能量色散谱仪(EDS),高分辨透射电子显微镜(HHRTEM)进行测试表征。结果表明所得产物为纯相锌黄锡矿CZTS纳米晶:FESEM结果表明样品由大量微球构成;且随着温度的增加颗粒尺寸逐渐增大。     

Crystallization kinetics of （Ni0.75Fe0.25）78-xNbxSi10B12 （x = 0, 5） amorphous alloys

Amorphous ribbons of （Ni0.75Fe0.25）78-xNbxSi10B12 （x = 0, 5） were prepared by a single roller melt-spinning technique in air atmosphere. The crystallization kinetics of the alloys were investigated by means of continuous heating, and the activation energies of the alloys were calculated using Kissinger plot method and Ozawa plot method on the basis of differential thermal analysis data. The crystallization products were analyzed by X-ray diffraction. After the （Ni0.75Fe0.25）78Si10B12 amorphous alloy was annealed at the temperatures 715 and 745 K, a single phase of γ-（Fe, Ni） solid solution with grain sizes of about 10.3 and 18.5 nm, respectively, precipitates in the amorphous matrix. The crystallized phases are γ-（Fe, Ni） solid solution, Fe2Si, Ni2Si, and Fe3B after annealing at 765 K. The （Ni0.75Fe0.25）73NbsSi10 B12 amorphous alloy was annealed at 720, 750, and 800 K; and the crystallization phases, γ（Fe, Ni） solid solution, （Fe, Ni）23B6. Ni31Si12 and Nb2NiB0.16 form simultaneously.     

溶剂热合成长径比可控锐钛矿型二氧化钛纳米棒（英文）

通过溶剂热法成功合成具有单分散特性的锐钛矿型二氧化钛纳米棒。通过改变实验条件,如:反应温度,合成时间等可以控制纳米棒的长径比。讨论了其晶体生长机制以及其形貌演变规律。为在液相条件下合成形貌可控的纳米晶提供了一种新的方法。     

亚砜KSO萃取Pd（Ⅱ）的机理

在前文（１）证实亚砜（ＫＳＯ）与ＰｄⅡ）形成萃合物为双核ｔｒａｎｓ－（ＰｄＬｃｌ２）２的基础上考察氢离子浓度、氯离子浓度以及亚砜ＫＳＯ浓度对萃取分配比的影响，推测了ＫＳＯ萃了Ｐｄ（Ⅱ）的机理。     

降低在浆萃取Au（Ⅲ）过程中的萃取剂损失

N.N—二仲辛基乙酰胺(N503)盐酸体系溶剂在浆萃取Au(Ⅲ)过程中,由于Si,Fe,Mg,Al,Ca等元素形成了溶剂污物,造成了萃取剂的大量损失。在表面化学分析的基础上分别研究了体系酸度、温度以及搅拌速度对溶剂污物形成的影响,结果表明搅拌速度及酸度是影响溶剂污物形成的主要因素,温度的升高亦有利于降低萃取剂损失。此外还研究了在萃取剂中加入调整剂及利用絮凝剂和表面活性剂对矿浆进行预处理,结果表明矿浆预处理后萃取剂损失能明显降低。     

NMP/DMF对溶剂热法合成[Zn4O（BDC）3]8的影响及框架-溶剂相互作用机制（英文）

为探究溶剂对合成有机金属框架化合物的影响机制,采用实验和DFT理论计算相结合的方法,研究溶剂N,N-二甲基甲酰胺(DMF)和N-甲基-2-吡咯烷酮(NMP)对溶剂热法合成有机金属框架材料[Zn4O(BDC)3]8的影响及溶剂与框架间的微观作用机制。粉末X射线衍射(XRD)和扫描电镜(SEM)结果表明,NMP在[Zn4O(BDC)3]8孔道中的吸附力较DMF的弱,NMP分子更容易从框架中脱除;热重(TG)和热重-红外联用(TGA/FT-IR)结果表明,以DMF为溶剂合成的[Zn4O(BDC)3]8的热分解温度和热稳定性较高;氮气等温吸附实验(BET)发现,以NMP为溶剂合成的[Zn4O(BDC)3]8的气体吸附性能更强,兰缪尔比表面积高于用DMF合成的[Zn4O(BDC)3]8。调控介电常数设定溶剂分别为NMP和DMF,用COSMO溶剂化方法对溶剂分子与框架化合物基本结构单元Zn4O(BDC)3间相互作用模型进行几何优化计算,发现溶剂设定为NMP时Zn4O(BDC)3优化结构的总能量较溶剂设定为DMF时的高8.6405 k J/mol,这说明DMF分子与Zn4O(BDC)3间的结合力强于NMP分子的,溶剂化作用降低了Zn与O间的离子性;用DMol3在GGA-BLYP/DN水平计算了DMF、NMP或DEF溶剂分子在[Zn4O(BDC)3]8晶体孔道中的相互作用,与DMF相比,NMP在孔道中能量状态稳定性较差,在能量状态角度上NMP应最容易从框架材料孔道中脱除。研究结果说明NMP更有利于合成性质良好的[Zn4O(BDC)3]8,与DMF相比NMP与框架结构基元间的作用力较弱。     

亚砜萃取Pd（Ⅱ）的结构及性能研究

系统研究了不同结构的二烷基(芳基)亚砜对Pd(Ⅱ)的萃取性能,以及亚砜的结构对萃取性能的影响,还研究亚砜-Pd(Ⅱ)配合物的结构.     

CaB6的原位反应合成及其热电性能

CaB6作为一种新型的热电材料,原料丰富且环保。以硼粉和氢化钙粉为原料,通过放电等离子烧结原位反应合成成功制备出了CaB6块体材料。第一性原理计算结果表明,CaB6呈现金属输运特性。试验结果表明,CaB6呈现n型金属输运特性。在373~773 K测试温度范围内,功率因子随着温度的升高呈上升趋势,从2.86×10-3 W·m-1 K-2增加到3.6×10-3 W·m-1 K-2,热导率随着温度的升高呈下降趋势,从11.63 W·m-1 K-1减小到9.06 W·m-1 K-1,其中晶格热导率占主导,且晶格热导率随温度的变化趋势与理论计算结果一致。在1 673 K制得的CaB6样品在773 K取得最大ZT值,达到0.34。     

等离子喷涂Gd2Zr2O7-SrZrO3复合陶瓷涂层的微观结构和性能

通过固相反应法合成了Gd2Zr2O7-SrZrO3 (GZSZ,Gd2Zr2O7:SrZrO3=7:3)复合陶瓷粉末,并采用喷雾造粒法和大气等离子喷涂法分别制备了适合等离子喷涂使用的相应喷涂粉末及涂层。使用X射线衍射、扫描电子显微镜对粉末和涂层的相组成、显微结构进行分析。借助激光热导仪、高温热膨胀仪对涂层的热扩散系数和热膨胀系数、烧结系数进行了表征。结果表明,制备的GZSZ复合陶瓷粉末和涂层都由Gd2Zr2O7和SrZrO3两相组成,粉末中的Gd2Zr2O7为烧绿石结构,而涂层中的Gd2Zr2O7为萤石结构,SrZrO3都为钙钛矿结构。制备态GZSZ涂层的孔隙率为~14%。GZSZ涂层1400℃热处理5 h后的热膨胀系数为(9.8~11.2)×10-6 K-1。制备态GZSZ涂层的热导率为~0.8 W·m-1·K-1,与制备态SrZrO3涂层的热导率~1.0 W·m-1·K-1相比降低~20%。1400℃热处理360 h后GZSZ涂层的热导率增加到~1.5 W·m-1.K-1。综上表明,GZSZ涂层是一种很有前景的复合陶瓷热障涂层材料。     

热压烧结制备Cu/FeCoCr复合材料的显微组织及热物理性能

利用相图计算的CALPHAD方法和超音雾化制粉技术,在CuFeCoCr体系中设计并制备了一系列微米级复合粉体。通过热压烧结方法在烧结温度为950℃,烧结压力为45 MPa的工艺条件下成功获得块体复合材料。研究了块体复合材料中Cu含量对显微组织,热导率,热膨胀系数以及显微硬度的影响。结果表明:CuFeCoCr块体复合材料均由fcc富铜相和fcc富铁钴铬相组成。该系列复合材料经600℃时效处理8 h后,其热膨胀系数变化范围为5.83×10-6~10.61×10-6 K-1,热导率变化范围为42.17~107.53 W·m-1·K-1。其中Cu55(Fe0.37Cr0.09Co0.54)45复合材料表现出良好的综合性能,即其热膨胀系数和热导率分别为9.08×10-6K-1和91.09 W·m-1·K-1,与电子封装半导体材料的热膨胀系数相匹配。     

Effects of heat treatment on the properties of powder injection molded AIN ceramics

The effects of two different heat-treatment atmospheres,nitrogen atmosphere and reducing nitrogen atmosphere with carbon,on the properties of Y2O3-doped aluminum nitride (AlN) ceramics were investigated.The AlN powder as a raw material was synthesized by self-propagating high-temperature synthesis (SHS) and compacts were fabricated by employing powder injection molding technique.The polymer-wax binder consisted of 60 wt.% paraffin wax (PW),35 wt.% polypropylene (PP),and 5 wt.% stearic acid (SA).After the removal of binder,specimens were sintered at 1850℃ in nitrogen atmosphere under atmospheric pressure.To improve the thermal conductivity,sintered samples were reheated.The result reveals that the heat-treatment atmosphere has significant effect on the properties and secondary phase of AlN ceramics.The thermal conductivity and density of AlN ceramics reheated in nitrogen gas are 180 W·m-1 K-1 and 3.28 g,cm-3 and the secondary phase is yttrium aluminate.For the sample reheated in reducing nitrogen atmosphere with carbon,the thermal conductivity and density are 173 W.m-1.K-1 and 3.23 g·cm-3,respectively,and the secondary phase is YN.     

可加工AlN-BN复合陶瓷的制备

以碳热还原法合成的 AlN 粉末和市售 BN 粉末为原料,添加 5%Y2O3 为烧结助剂,利用无压烧结制备 AlN-15BN复合陶瓷,研究了烧结温度对 AlN-15BN 复合陶瓷相变、致密度、微观结构以及性能的影响,结果表明:Y2O3 可与 AlN粉末表面的 Al2O3 发生反应生成液相促进烧结,随着烧结温度的升高,复合陶瓷的致密度、热导率和硬度逐渐增加,片状的 BN 形成的卡片房式结构会阻碍复合陶瓷的收缩和致密。在 1 850℃烧结 3 h,可以制备出相对密度为 86.4%,热导率为104.6 W?m-1?K-1,硬度为 HRA56.2的 AlN-15BN复合陶瓷。研究表明,通过添加加工性能良好的 BN制备可加 AIN-BN复合陶瓷,是解决 AIB 陶瓷复杂形状成形问题的一个重要途径。     

复合钙钛矿型Ba(Zn1/3Ta2/3)O3陶瓷作为热障涂层陶瓷层材料的性能评价

以BaCO₃、ZnO、Ta₂O₅为原料,采用固相反应法制备了Ba(Zn_1/3Ta_2/3)O₃(BZT)陶瓷材料。对BZT的物相结构、高温相稳定性、热导率、热膨胀系数和喷涂工艺适应性进行表征研究,并与同类Ba(Mg_1/3Ta_2/3)O₃(BMT)、Ba(Ni_1/3Ta_2/3)O₃(BNT)和Ba(Sr_1/3Ta_2/3)O₃(BST)对比,以评价BZT作为热障涂层陶瓷层材料的应用潜力。结果表明,BZT在室温至1500℃内无相变,且经1600℃长时处理48 h后不分解,表现出良好的高温相稳定性;在1200℃,BZT的热导率仅为1.65 W·m^-1·K^-1,明显低于BMT(2.57 W·m^-1·K     

Thermal conductivity behavior of SPS consolidated AIN/Al composites for thermal management applications

AIN/Al composites are a potentially new kind of thermal management material for electronic packaging and heat sink applications.The spark plasma sintering(SPS)technique was used for the first time to prepare the AIN/Al composites,and attention was focused on the effects of sintering parameters on the relative density,microstructure and,in particular,thermal conductivity behavior of the composites.The results showed that the relative density and thermal conductivity of the composites increased with increasing sintering temperature and pressure.The composites sintered at 1550℃ for 5 min under 70 Mpa showed the maximum relative density and thermal conductivity,corresponding to 99% and 97.5 W·m-1·K-1,respectively.However,the thermal conductivity of present AIN/Al composites is still far below the theoretical value.Possible reasons for this deviation were discussed.     

Fabrication, microstructure and properties of SiCp/Cu heat sink materials

Cu-coated powder was fabricated by electroless plating process, and the composition and morphology of coated powder were studied.Moreover, Cu-30, 40, 50 vol.%SiCp heat sink materials were fabricated by hot pressing using coated and uncoated powder.And the microstructure and thermophysical properties of the heat sink materials were also studied.The results show that SiCp particles distribute uniformly in heat sink materials and the interface between SiCp particles and Cu matrix is clear and well bonded.On the condition of same volume fraction of SiCp, the thermal conductivity of the material using coated powder is larger than that of the material using uncoated powder.Under experiment conditions, the thermal conductivity and coefficient of thermal expansion of Cu-30 vol.%SiCp heat sink material is 236.2 W·m-1·K-1 and 9.9×10-6/K (30-200 ℃) respectively.It provides important reference data for future experiments.     

钛酸钾晶须/聚丙烯导热抗静电复合材料的制备与性能

采用热压成型工艺制备了导电钛酸钾晶须(PTWs)/聚丙烯(PP)复合材料,研究了晶须用量对复合材料导热性能、抗静电性能和力学性能的影响。结果表明,随着PTWs用量的增加,PTWs/PP复合材料的热导率提高、体积电阻率和摩擦静电荷下降;材料的拉伸强度、弯曲强度均随PTWs用量的增加呈先增大后减小的趋势;而熔体流动速率则呈增大趋势。当PTWs体积分数达到0.38%时,材料的热导率达到最大值0.5105 W.m-1.K-1,电阻率降低到109Ω.cm以下,满足一般抗静电材料的要求。