TiO2/Al2O3-Al2O3-TiO2/Al2O3绝缘结构的真空沿面闪络特性

基于变插入层介电常数的多层绝缘结构能改善电场分布、提高真空沿面闪络特性.通过真空热压烧结制备了TiO2/Al2O3-Al2O3-TiO2/Al2O3(A-B-A)3层绝缘结构,A层w(TiO2)为0.5%到20%.测量了该绝缘结构的真空沿面闪络特性,发现闪络特性随w(TiO2)的增加而提高,当w(TiO2)为20%时,其脉冲初次闪络电压较同等厚度的Al2O3陶瓷提高了63%.研究发现:A层的介电常数可由w(TiO2)调控,介电常数的增大能有效降低真空-绝缘子-阴极三结合点处的电场强度;A层表面存在的TiO2颗粒可以减小二次电子发射系数并改善表面电荷分布;TiO2的电导率虽比Al2O3高,但其仍为绝缘体,即使TiO2含量较高时也不会形成贯穿的导电通道.     

CaO-ZrO2-TiO2-Al2O3-B2O3-SiO2玻璃陶瓷的制备及化学稳定性研究

玻璃陶瓷是固化处理中、高放废物和α废物较为理想的候选材料之一。研究了特定条件下制备的CaO-ZrO2-TiO2-Al2O3-B2O3-SiO2体系玻璃陶瓷在水淬和空气中自然冷却的两种冷却制度对其结晶行为和显微结构的影响,用粉末浸泡实验方法测试了其化学稳定性。结果表明:自然冷却形成的玻璃陶瓷晶相主要是ZrSiO4和ZrTiO4;在25～70℃范围内,温度对玻璃陶瓷浸出率无明显影响,90℃下浸出率比25℃,40℃,70℃的浸出率高一个数量级;7 d元素总的归一化浸出为1.87 g/m2。     

纳米Fe2O3-Al2O3复合材料的制备

采用溶胶-凝胶表面包覆法制备了纳米Fe₂O₃-Al₂ O₃复合材料, 利用X射线衍射和透射电镜对样品的物相、 粒度和形貌进行了研 究. 结果表明, α-Fe₂O₃掺杂降低了Al₂O₃相变温度, 在900 ℃可以得到稳定的α-Al₂O₃相.     

在Na3AlF6-AlF3-CaF2-LiF-Al2O3体系中低温铝电解

Based on the main physico-chemical properties of Na₃AlF₆-AlF₃-CaF₂-LiF-Al₂O₃ system studied, including liquidus temperature、electrical conductivity and bath density, a laboratory scale vertical discharging aluminum type electrolysis cell of about 100A capacity was run with TiB₂ cathodes and low molar ratio(1.5～2.0) electrolytes at 800～930℃ range. Aluminum metal was obtained with 84.6%～88.3% current efficiencies and 11.54～11.83 kW^.h/kg specific energy consumption.     

Crystallization Mechanism of Na2O-CaO-Al2O3-SiO2-F- Glass Containing Cr2O3

The effect of Cr₂O₃ on the nucleation and crystallization of Na₂O-CaO-Al₂O₃-SiO₂-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1.5 % (mass fraction) Cr₂O₃ can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr₂O₄] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO₃ grew epitaxially.     

Al2O3-SiO2∶Ln3+发光陶瓷的合成及发光行为

采用溶胶-凝胶法合成出了Al     

固体超强酸S2O8^2—／ZrO2—Al2O3催化合成对羟基苯甲酸乙酯

报道了一种以对羟基苯甲酸和乙醇为原料合成对羟基苯甲酸乙酯的新方法,即在固体超强酸S2O8^2-/ZrO2-Al2O催化下,用子筛作脱水剂,采用索氏提取器进行回流脱水直接酯化。并考察醇酸比、反应时间、催化剂用量等因素对酯产率的影响。     

Effect of Fe2O3 on the size and components of spinel crystals in the CaO-SiO2-MgO-Al2O3-Cr2O3 system

size of spinel crystals in the CaO-SiO₂-MgO-Al₂O₃-Cr₂O₃ system was investigated using lab experiments carried out in a carbon tube furnace. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) were used to analyze the microstructure, components, and the mineral phases of synthetic slags. FactSage 7.1 was used to calculate the crystallization process of the molten slag. The results showed that the addition of Fe₂O₃ promoted the precipitation of spinel crystals and inhibited the formation of dicalcium silicate. The size of spinel crystals increased from 2.74 to 8.10 μm and the contents of chromium and iron in the spinel varied as the Fe₂O₃ addition was increased from 0 to 20wt%. Fe₂O₃ thermodynamically provided the spinel-forming components to enhance the formation of FeCr₂O₄, MgFe₂O₄, and Fe₃O₄. The addition of Fe₂O₃ increased the fraction of liquid phase in a certain temperature range and promoted diffusion by decreasing the slag's viscosity. Therefore, Fe₂O₃ is beneficial to the growth of spinel crystals in stainless steel slag.     

Sb2Se3-Sb2S3两端叠层薄膜太阳能电池

设计并制备一种全锑基两端叠层薄膜太阳能电池，其结构为ITO/CdS/Sb₂S₃/Au/ZnO/Sb₂Se₃/Au.通过快速热蒸发法制备Sb₂Se₃和Sb₂S₃薄膜，该薄膜具有良好的结晶性.测试表明，器件中各层薄膜的能级互相匹配，并且可实现光谱的分段利用. Sb₂Se₃-Sb₂S₃两端叠层电池的光电转换效率达到3.25%,其开路电压为0.98 V,可基本实现开压叠加.     

Bi_2Se_3、Bi_2Te_3和Sb_2Te_3的声子和热力学性质的第一性原理研究

基于第一性原理的密度泛函理论,在未考虑和考虑自旋-轨道耦合(SOC)的情况下分别优化拓扑绝缘体Bi2Se3、Bi2Te3和Sb2Te3的结构,计算它们的声子谱及热力学性质.基于广义梯度交换相关泛函及SOC效应,计算得到三种物质的声子频率比不考虑SOC时更吻合实验数据.最后计算出三种物质的赫尔姆赫兹自由能F,内能E,等体热容CV和熵S随温度的变化趋势.     

BiFeO3掺杂Pb（In1/2Nb1/2）O3-Pb（Mg1/3Nb2/3）O3-PbTiO3陶瓷的制备与磁电性能研究

以固相合成法制备了铁酸铋（BiFeO₃,简称BFO）掺杂的铌铟酸铅-铌镁酸铅-钛酸铅（Pb（In_1/2Nb_1/2）O₃-Pb（Mg_1/3Nb_2/3）O₃-PbTiO₃,简称PIN-PMN-PT）多铁性陶瓷材料,X射线衍射（XRD）测试结果表明：样品具有钙钛矿结构,电滞回线显示其铁电性良好,剩余极化值（P_r）可达18 μC·cm^-2.由于BiFeO₃掺杂后,样品电矩减小,氧空位增多,使其铁电畴翻转困难,样品的电性能略有下降,但是其磁性能随BiFeO₃掺入量的增加而逐渐增强,且样品居里温度（T_m）为200℃左右.该材料在电磁学领域有望成为具有应用前景的多铁性材料.     

纳米Al2O3颗粒对Cu-Al2O3性能的影响

采用溶胶-凝胶法制备纳米Al₂O₃颗粒,通过粉末冶金法制备氧化铝铜（Cu-Al₂O₃）。采用X射线光电子能谱仪、扫描电子显微镜、洛氏硬度仪和涡流计分别测试了Cu-Al₂O₃的结合能、微观组织、硬度和导电率。结果表明：随Al₂O₃颗粒含量的增加,Cu-Al₂O₃的硬度先升高后降低,当Al₂O₃颗粒的质量分数达到0.084%时,Cu-Al₂O₃的硬度达到最大值75.73（HRB）。Cu-Al₂O₃的导电率随着Al₂O₃颗粒含量的增加逐渐下降。Al₂O₃颗粒的质量分数为0.084%时为最佳值,Cu-Al₂O₃的硬度达到最大值,导电率达到69.1% IACS。     

PREPARATION OF COMPLEX ZrO2-Y2O3 SOL

Complex ZrO₂-Y₂O₃ sol were prepared from precursors of inorganic salts and metal alkoxides. The processes for complex ZrO₂-Y₂O₃ sol preparation and purification, the sol-gel transformation and the characterization of the sol from the two kinds of precursors were discussed and compared. It was found that the colloidal particles were amorphous in nature, and extremely fine (<10nm) in the both cases. ZrO₂-Y₂O₃ coatings on GH220 superalloy samples MCrAlX (M=Fe, Co, Ni, X=Y, Ta,Hf…) pre-coated) were prepared using sols from the two different processes and tested at 1000 ℃ for 100 h in laboratory air. Results showed that only the coatings from the metal alkoxides derived sol offered excellent oxidation resistance.     

Yb2O3、Al2O3、TiO2对Yb-TZP材料性能的影响

用超细ZrO     

SO42-/Bi2O3-Al2O3催化水合肼还原硝基苯制备苯胺

以Bi(NO3)3和AlCl3为原料,采用共沉淀法制备了固体酸催化剂SO42-/Bi2O3-Al2O3。探讨了SO42-/Bi2O3-Al2O3催化水合肼还原硝基苯的催化活性。结果表明:催化剂中n(Bi):n(Al)=1:15,以10%的(NH4)2SO4浸渍所得的催化剂具有较高活性。红外光谱表明,催化剂中存在B酸中心,能有效地提高催化剂的性能。此还原方法反应条件温和,催化剂制备简单。     

Preparation, crystallization, and wetting of ZnO-Al2O3-B2O3-SiO2 glass-ceramics for sealing to Kovar

A novel type of ZnO-Al₂O₃-B₂O₃-SiO₂ glass-ceramics sealing to Kovar in electronic packaging was developed, whose thermal expansion coefficient and electrical resistance are 5.2×10-6/℃ and over 1×1013 Ω·cm, respectively. The major crystalline phases in the glass-ceramic seals were ZnAl₂O₄, ZnB₂O₄, and NaSiAl₂O₄. The dielectric resistance of the glass-ceramic could be remarkably enhanced through the control of alkali metal ions into crystal lattices. It was found that crystallization happened first on the surface of the sample, leaving the amorphous phase in the inner, which made the glass suitable for sealing. The glass-ceramic showed better wetting on the Kovar surface, and sealing atmosphere and temperature had great effect on the wetting angle. Strong interracial bonding was obtained, which was mainly attributed to the interracial reaction between SiO₂ and FeO or Fe₃O₄.     

XPS Study of CeO2/Al2O3 film

The redox capacity of CeO₂/Al₂O₃ thin film which was prepared by sol-gel method has been investigated by X-ray Photoelectron Spectrascopy (XPS). The results showed that the thin film was easier to be reduced and re-oxidized than pure CeO₂ powder. The key role played by oxygen vacancies which were created from the interaction between CeO₂ and Al,O, was also discussed.     

K2O—KgO—SiO2—B2O3—F系统生物玻璃玻璃的分相行为研究

通过一系列实验，对K2O－MgO-SiO20-B2O3-F系统玻璃的分相行为进行了研究，考察了不同组份及热处理对分相行为及玻璃微观结构的影响。结果表明，适当含量的Al2O3,P2O5,CaO的引入，有助于获得理想的分相结构，对最终产品的性能将起到重要作用。