hafnium diboride

• 分子结构分类: 无机化合物 - 混合金属/非金属化合物 - 各种混合金属/非金属
• 英文名称: hafnium diboride
• 英文别名: borane;hafnium
• 化学式: B₂Hf
• 分子量: 200.112
• InChiKey: RYDJHVMWRZUZBZ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -2.37
• 重原子数：
  3.0
• 可旋转键数：
  0.0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  0.0
• 氢给体数：
  0.0
• 氢受体数：
  0.0

反应信息

• 作为反应物：
  描述：

  silicon carbide 、 hafnium diboride 以 neat (no solvent, solid phase) 为溶剂， 生成
  参考文献：
  名称：

  Thermal and Electrical Transport Properties of Spark Plasma-Sintered HfB2 and ZrB2 Ceramics

  摘要：

  The thermal and electrical transport properties of various spark plasma-sintered HfB2- and ZrB2-based polycrystalline ceramics were investigated experimentally over the 298-700 K temperature range. Measurements of thermal diffusivity, electrical resistivity, and Hall coefficient are reported, as well as the derived properties of thermal conductivity, charge carrier density, and charge carrier mobility. Hall coefficients were negative confirming electrons as the dominant charge carrier, with carrier densities and mobilities in the 3-5 x 10(21) cm(-3) and 100-250 cm(2). (V. s)(-1) ranges, respectively. Electrical resistivities were lower, and temperature coefficients of resistivity higher, than those typically reported for HfB2 and ZrB2 materials manufactured by the conventional hot pressing. A Wiedemann-Franz analysis confirms the dominance of electronic contributions to heat transport. The thermal conductivity was found to decrease with increasing temperature for all materials. Results are discussed in terms of sample morphology and compared with data previously reported in the scientific literature.

  DOI：

  10.1111/j.1551-2916.2011.04411.x
• 作为产物：
  描述：

  hafnium borohydride 以 neat (no solvent) 为溶剂， 生成 hafnium diboride
  参考文献：
  名称：

  用于硅上光电集成的外延半金属 HfxZr1−xB2 模板

  摘要：

  高质量的异质外延 HfxZr1-xB2 (x=0-1) 缓冲液直接生长在 Si(111) 上。薄膜结构的成分依赖性和从头算弹性常数用于表明六方 HfxZr1-xB2 在生长时具有拉伸面内应变 (0.5%)。高质量的 HfB2 薄膜也在应变补偿 ZrB2 缓冲的 Si(111) 上生长。厚 ZrB2 薄膜的初始反射率测量与第一性原理计算一致，该计算预测 HfB2 的反射率在 2-8eV 范围内相对于 ZrB2 增加 20%。这些可调的结构、热弹性和光学特性表明 HfxZr1-xB2 模板应该适用于 III 族氮化物与 Si 的广泛集成。

  DOI：

  10.1063/1.2403189

文献信息

• New criteria for the applicability of combustion synthesis: The investigation of thermodynamic and kinetic processes for binary Chemical Reactions
  作者：Xiaoming Tan、Xianli Su、Yonggao Yan、Ctirad Uher、Qingjie Zhang、Xinfeng Tang

  DOI：10.1016/j.jallcom.2020.158465

  日期：2021.4

  Combustion synthesis is a novel technique that utilizes the exothermic heat of a chemical reaction to maintain the reaction and to rapidly prepare materials. But, hitherto, none of unified criterion for the validation of combustion synthesis has been proposed. Herein, we proposed the conditions need to be met. In terms of kinetics, at the adiabatic temperature (Tad), the diffusion distance of atoms

  燃烧合成是一种利用化学反应的放热来维持反应并快速制备材料的新技术。但是，迄今为止，尚未提出用于验证燃烧合成的统一标准。在此，我们提出了需要满足的条件。就动力学而言，在绝热温度（T ad）下，原子的扩散距离（升Ť广告）在0.1 s内应大于反应物的粒径（d）， 那是， 升Ť广告≥d。对于满足T ad / T m，L的系统≥1（其中T m，L是反应物的低熔点成分的熔点），液相的存在将原子的扩散距离从纳米显着增加到数十微米，从而成为标准升Ť广告≥d简化为T ad / T m，L≥在大多数情况下为1。在热力学方面，系统需要确保反应成分处于激活状态，即T ad / T m，H ≥0.7，其中T m，H是高熔点组分的熔点。本研究提出的SHS反应标准进一步提高了对SHS反应的理论理解，并为探索二元和多组分化合物的超快合成提供了指导。
• Ball Milling-Induced Combustion in Powder Mixtures Containing Titanium, Zirconium, or Hafnium
  作者：L. Takacs

  DOI：10.1006/jssc.1996.0267

  日期：1996.8

  induces self propagating high temperature reactions in many highly exothermic powder mixtures. This phenomenon has been studied in a variety of reactions with titanium, zirconium, and hafnium. Several oxides (CuO, Cu2O, NiO, Fe3O4, and ZnO) were reduced with Ti, Zr, and Hf and the borides, carbides, silicides, and sulfides of these metals were prepared from elemental mixtures. The ignition time is much shorter

  球磨在许多高度放热的粉末混合物中引起自蔓延的高温反应。已经在与钛，锆和ha的各种反应中研究了这种现象。用Ti，Zr和Hf还原了几种氧化物（CuO，Cu 2 O，NiO，Fe 3 O 4和ZnO），并从元素混合物中制备了这些金属的硼化物，碳化物，硅化物和硫化物。当氧气或硫参与反应时，Zr的点火时间比Ti或Hf的点火时间短得多，但是对于硼化物，碳化物和硅化物的形成没有观察到类似的变化。提示氧在ZrO 2中快速扩散，而硫很可能在ZrS 2中扩散对此行为负责。
• Titanium, zirconium, and hafnium tetrahydroborates as "tailored" CVD precursors for metal diboride thin films
  作者：James A. Jensen、John E. Gozum、Deborah M. Pollina、Gregory S. Girolami

  DOI：10.1021/ja00213a058

  日期：1988.3

  retention of unsaturated tin in the product is precluded either by conversion to four-coordinate Sn or by hydride bridging to tin. This is a conclusion also evident from our study2I of the products of reductive elimination of methane from AlMe, and ReH,(PR3),. Our consistent finding that hydride ligands in heterometallic polyhydride clusters do not rapidly migrate past Cu, Ag, and now S n centers suggests

  不饱和锡在产品中的保留通过转化为四配位锡或通过氢化物桥连到锡来排除。从我们对从 AlMe 和 ReH(PR3) 中还原消除甲烷的产物的研究 2I 中，这一结论也很明显。我们一致发现，异金属多氢化物簇中的氢化物配体不会迅速迁移通过 Cu、Ag 和现在的 S n 中心，这表明氢~柱塞、~~*~~氢在表面上的迁移可能会遇到显着的激活障碍。， ,
• Silicothermic synthesis of phase‐pure HfB ₂ fine powder
  作者：Jinhua Zhang、Si Xiong、Jingran Wang、Yue’e Ni、Changming Ke

  DOI：10.1111/jace.17498

  日期：2021.2

  silicate could be readily recycled and used as a precursor for preparing many other valuable materials due to absence of foreign salts (eg halides, especially in the molten salt‐assisted synthesis process) in the synthesis process, and the relevant environmental concerns could be alleviated. Using excessive amount of 20 wt% Si and 15 wt% Na2B4O7 as compensation for the evaporation loss of silicon, in the

  通过新颖的可持续硅热法在1100°C下用廉价的原料HfO 2，Na 2 B 4 O 7和Si制备了相纯和纳米级的二硼化ha （HfB 2）细粉。通过将钠盐作为Na 2 O的来源引入到批料混合物中，熔体中的SiO 2 / Na 2 O模量从5：1降低到2：1，原始的水不溶性副产物SiO 2被在测试温度下熔化并转化为水溶性硅酸钠（Na 2 Si 2 O 5通过简单的热水洗涤容易地从反应的物质中除去）。因此，由于合成过程中不存在外来盐（例如，卤化物，特别是在熔融盐辅助合成过程中），以及相关的环境因素，硅酸钠水可以很容易地回收并用作制备许多其他有价值材料的前体。担忧可以缓解。在还原过程中，使用过量的20 wt％Si和15 wt％Na 2 B 4 O 7来补偿以SiO（g）形式存在的硅和B 2 O 3形式的硅的蒸发损失，反应程度很高。达到HfO 2和Na 2 B 4 O 7在1100°C下完全转化为HfB
• Fabrication of UHTCs by Conversion of Dynamically Consolidated Zr+B and Hf+B Powder Mixtures
  作者：Mathieu Brochu、Bryan Gauntt、Tony Zimmerly、Alicia Ayala、Ronald Loehman

  DOI：10.1111/j.1551-2916.2008.02550.x

  日期：2008.9

  Mixtures of Zr+B and Hf+B were shock compacted into bulk samples possessing relative densities above 95.5% and were subsequently converted to ZrB2 and HfB2 ceramic components by a heat treatment. The conversion temperature was varied between 1600° and 2000°C. The conversion temperature was found to have no effect on the final density of the ceramics. Theoretical densities of 72% and 62% were obtained for the converted ZrB2 and HfB2 ceramics, respectively. Increasing the heat‐treatment temperature promoted grain growth rather than densification for the ZrB2 samples. The grain size increased from 1.8±0.6 to 5.6±1.3 to 8.5±3.3 μm, for heat treatments at 1600°, 1800°, and 2000°C, respectively. No grain growth was observed for the HfB2 system, which exhibited a grain structure of 5.0±1.6, 3.3±1.5, and 4.4±2.2 μm for the same temperature range studied. Microhardness values for the ZrB2 decreased from 19.4±0.4 to 17.2±0.6 down to 13.7±0.6 GPa, while similar hardness results of 19.1±0.8, 17.1±1.0, and 17.8±0.5 GPa were observed for the HfB2 samples.

  锆基(Zr+B)和铪基(Hf+B)的混合物通过冲击压缩工艺形成具有95.5%以上相对密度的块状样品，随后经热处理转化为氧化锆(ZrB₂)和氧化铪(HfB₂)陶瓷部件。热处理的转化温度在1600°至2000°C之间变化。研究发现，转化温度对最终陶瓷的密度无显著影响。经过转化的ZrB₂和HfB₂陶瓷的理论密度分别达到72%和62%。对于ZrB₂样品，提高热处理温度会促进晶粒生长而非致密化。其晶粒尺寸随热处理温度从1600°、1800°到2000°C分别增加，从1.8±0.6 μm增长至8.5±3.3 μm。而HfB₂系统未观察到晶粒生长现象，在相同温度范围内，其晶粒尺寸分别为5.0±1.6 μm、3.3±1.5 μm和4.4±2.2 μm。ZrB₂的显微硬度从19.4±0.4 GPa逐渐降至13.7±0.6 GPa，而HfB₂样品的硬度值则保持在17.1±1.0 GPa至19.1±0.8 GPa之间，变化不大。