Bismuth borate composite microwave ceramics synthesised by different ratios of H3BO3 for ULTCC technology

Bi₃B_5+xO_12+3x/2 (x = 0∼6) compounds were fabricated by a conventional solid-state reaction method. The microwave dielectric properties, sintering behaviour, crystal structure, and phase evolution of the ceramics were investigated. All samples densified at ultra-low temperatures (575∼700 °C). As x increased, the phase composition of the ceramics gradually changed from mixed Bi₄B₂O₉ and Bi₃B₅O₁₂ phases to a single Bi₆B₁₀O₂₄ phase. The ceramic with x = 4 exhibited the best microwave dielectric properties of ε_r = 12.14, Q × f = 14,800 GHz, and τ_ƒ = −72 ppm/°C at 625 °C. The microwave dielectric properties deteriorated as x increased further. Moreover, the ceramics were proven to cofire with Al and Ag, indicating that they are candidates for ultra-low-temperature cofired ceramic devices.     

Growth behavior of aluminum borate whiskers on zirconia toughened alumina (ZTA) particle surface

In this work, B₄C-covered zirconia-toughened alumina (ZTA) particles are prepared and oxidised at 1050 °C for different times (0, 2, 4, and 8 h) in air. The X-ray diffraction and electron probe micro-analysis results show that the covering layer is mainly composed of oxide B₂O₃ intermetallics, residual B₄C particles, and Al₁₈B₄O₃₃ whiskers. The scanning electron microscopy results show that the growth of Al₁₈B₄O₃₃ whiskers on the ZTA particles enhances with increasing heat preservation time; the optimum holding time is determined to be 8 h Al₂O₃ in the ZTA particles diffuse into the covering layer and combine with B₂O₃ to form Al₁₈B₄O₃₃ whiskers; the Al₁₈B₄O₃₃ whiskers grow via the liquid-solid mechanism.     

低品位硼矿的富集加工技术

报道了青海大柴旦地区低品位硼矿富集加工的新工艺，该工艺使硼矿品位30％－35％，B2O3收率大于80％，该工艺路线已工业化。     

Cationic substitution engineering achieves higher efficiency and thermal stability of Cr3+-activated phosphor for pepper (Capsicum annuum L.) development

Nowadays, near-infrared phosphor-converted light emitting diodes (NIR pc-LEDs) attract wide attention since the NIR spectroscopy technique can exert itself in many fields. However, most of the developed NIR phosphors are still not commercially viable, because of low internal/external quantum yield and poor thermal resistance. Therefore, it is urgent to develop an efficient irradiance and thermal stable NIR phosphor. In this work, the new GdAl_3-x-yGa_y(BO₃)₄: xCr³⁺ phosphors, compared with the original phosphor (x = 0.03, y = 0), when x = 0.03, y = 0.2, the luminescence intensity increased by 2.1 times, and the thermal resistance jumped from 92.0% to 96.7%. At the same time, with the increase of Ga³⁺, the spectra were gradually red shifted and FWHM widened, attributing to the nephelauxetic effect and the electron-phonon coupling effect enhanced, respectively. Particularly, under 420 nm excitation, the internal and external quantum yield of GdAl_2.77Ga_0.2(BO₃)₄: 0.03Cr³⁺ were 93.4% and 35.5%, respectively, which is higher than the previous research. The electric-optical conversion efficiency of the pc-LED was 10.76%. Finally, the phosphor application experiments revealed that the prepared phosphor has a very high commercial application potential.     

硼镁石制取硼酸钙工艺研究

介绍了在现有生产硼砂生产线上，以硼镁石为原料，在催化剂作用下，通过碳解反应获得多硼酸钠溶液，再与石灰乳反应(合成反应)制取硼酸钙的新工艺。研究了诸多工艺参数对碳解反应的影响及合成硼酸钙的工艺条件，当硼粉品位为12％，反应时间24h，CO2浓度30％，碳解压力0．6MPa，温度130℃，碳解反应最佳条件硼矿／纯碱比为5，液固比2．5：1；合成反应硼钙比1：3，温度110-120℃，最佳反应时间2h。     

硼酸镁晶须的合成研究

报道了硼酸镁晶须的合成研究结果。硼酸镁晶须是一种性能价格比高的晶须产品，利用熔盐法合成出长10—50μm、直径0．5—2μm的硼酸镁晶须。还就硼酸镁晶须增强复合材料的研究和硼酸镁晶须工业化的前景作了展望。     

纳米水合硼酸锌的合成

通过改进传统的七水合硼酸锌 (2ZnO·3B2 O3 ·7H2 O)的合成工艺条件 ,合成了纳米级硼酸锌并对产品进行了x -射线、透射电镜等测试表征。     

Synthesis, structural characterization and ethylene polymerization behavior of complex [Ph4P][CrCl3{HB(pz)3}] [HB(pz)3 = hydrotris(1-pyrazolyl)borate]

Reaction of CrCl₃(THF)₃ with K[HB(pz)₃] in THF leads to the formation of the complex K[CrCl₃{HB(pz)₃}] (1). The salt metathesis of complex 1 with [Ph₄P]Br in CH₂Cl₂ yields the complex [Ph₄P][CrCl₃{HB(pz)₃}](2). The structure of complex 2 · CHCl₃ has been determined by single crystal X-ray diffraction. In the anion the metal centre shows a distorted octahedral geometry with the hydrotris(1-pyrazolyl)borate bonded as N,N′,N″-donor tripod ligand and three chloride atoms completing the co-ordination sphere. Complex 2 in the presence of MAO leads to the formation of an active catalyst for the polymerization of ethylene.     

马来酸酐接枝聚乙烯对无卤阻燃PE-HD护套料的改性研究

研究了马来酸酐接枝聚乙烯对无卤抑烟阻燃PE-HD护套料的改性效果，并进行了增韧机理上的探讨。采用扫描电镜对复合材料进行了断面观察，并测试了材料的力学性能、流变性能、耐热性能和氧指数。结果表明，马来酸酐接枝聚乙烯能够极大地提高复合材料的界面相容性，增强材料的界面相互作用，提高阻燃剂微粒在树脂基体中的分散效果，同时形成了一个可塑性界面层，所以能够提高材料的韧性。     

硼酸锌微粉的合成及应用

本文介绍了用作阻燃剂的水合硼酸锌微粉的性质,合成方法和应用领域,并对如何制备纳米硼酸锌提出展望。