添加Bi2O3对ZnO-B2O3-P2O5-SrO体系封接玻璃结构和性能的影响

采用熔融法制备了ZnO-B2O3-P2O5-SrO-Bi2O3系无铅磷酸盐封接玻璃,研究了Bi2O3对该体系玻璃的结构、特征温度、热膨胀系数和化学稳定性的影响。结果表明,随Bi2O3含量的增加,玻璃的密度增大,Tg、Tf先下降后趋于平缓,玻璃的热膨胀系数先上升后趋于平缓;化学稳定性先增强后降低,当Bi2O3为7mol时,达到极小值。     

可见光响应Pt沉积La2O3/TiO2制备及其对甲苯的光热催化去除

以钛酸四丁酯和硝酸镧为原料,采用溶胶—凝胶法制备La2O3/TiO2,通过光沉积法在La2O3/TiO2表面负载纳米Pt粒子.采用XPS、FTIR、XRD、DRS、TEM和低温氮物理吸附对光催化剂的晶体结构、光谱特征和表面结构进行表征.考察了催化剂在可见光下对甲苯的去除性能和温度对催化剂去除甲苯的影响.结果表明,沉积的Pt以单质和吸附氧的形式存在,其中以吸附氧的形式为主.Pt的掺入没有引起TiO2相结构的变化,减小了晶粒尺寸并增大了催化剂的比表面积.纳米Pt均匀地分布在La2O3/TiO2上,尺寸分布比较均一,大约为5～10nm.Pt-La2O3/TiO2的表面羟基官能团伸缩振动明显增强,比TiO2和La2O3/TiO2具有更高的可见光催化活性.Pt-La2O3/TiO2对甲苯的降解率,随着温度的升高而增大,产生了与光催化作用平行的热催化作用.气相甲苯光热催化过程不是光催化与热催化的简单叠加,而是存在协同作用.     

MoO3-V2O5-P2O5-Fe2O3玻璃的制备及性能研究

制备了MoO3-V2O5-P2O5-Fe2O3系磷酸盐玻璃,研究了玻璃形成能力、热膨胀系数和抗潮解等性能.结果表明,MoO3-V2O5-P2O5-Fe2O3系统具有较宽的玻璃形成区和较强的玻璃形成能力,当MoO3/V2O5≈1.5时,玻璃形成能力最强.MoO3-V2O5-P2O5-Fe2O3玻璃的热膨胀系数约为60～110×10-7/℃,并且随着Fe2O3含量的增加而逐渐增大.加入适量的Fe2O3能够显著改善MoO3-V2O5-P2O5玻璃的抗潮解性能,在90℃的去离子水中的溶解速率达到8.0×10-9g·cm-2·min-1.     

超级电容器用（RuO2/SiO2）·nH2O复合薄膜电极的研究

以水合三氯化钌(RuCl3.3H2O)和正硅酸乙酯(TEOS)为原料,采用溶胶-热分解法制备了超级电容器用(RuO2/SiO2).nH2O复合薄膜电极材料。研究了热处理温度及热处理时间对电极材料电学性能的影响。借助CHI660C电化学工作站对薄膜材料的电化学性能进行了测试,采用SEM、XRD、FTIR等检测手段对复合材料的微观形貌、物相结构进行了分析。结果表明,固定水合三氯化钌和正硅酸乙酯的物质的量比为10∶3,当热处理温度和时间分别为350℃和2h时,复合薄膜电极具有优良的综合性能,比表面积为265.7m2/g,比电容最高为421F/g,充放电电流为0.1A时,内阻最高为0.72Ω。     

R2O3对装饰乳浊玻璃结构与性能的影响

通过将两种不同颜色的Na2O-CaO-SiO2系统乳浊玻璃在熔融状态时进行完全混合,获得类似天然石材条纹的乳浊玻璃。采用XRD、SEM等测试手段研究乳浊玻璃的分相过程,分析了R2O3(R=Al,B)含量变化对乳浊玻璃的显微结构及性能的影响。研究结果表明,该系统乳浊玻璃的乳浊机理是分相乳浊,着色剂对玻璃微观结构无显著影响;随着Al2O3含量增加,富磷相数量减少但其液滴尺寸增大。B2O3含量提高使富磷相尺寸减小,液滴尺寸和分布趋向均匀;Al2O3含量增加使玻璃的耐水性有所提高;而B2O3含量增加降低了玻璃的耐水性。     

V2O5-B2O3-TeO2体系低熔点玻璃形成规律及特性

较详细地研究了V2O5-B2O3-TeO2三元体系的熔化温度、冷却熔体的相组成及玻璃形成规律;并测试分析了V2O5-B2O3-TeO2三元体系玻璃的热性能和特征温度。结果表明,V2O5-B2O3-TeO2三元体系具有较低的熔化温度,存在3个不同的结晶区域和一个较广阔的玻璃形成区,其玻璃形成区域为:V2O50%～70%、B2O30%～30%、TeO230%～100%(均为摩尔分数);V2O5-B2O3-TeO2系玻璃具有较低的熔化温度和封接温度,是无铅低温封接玻璃的理想体系之一。     

含碱金属离子的CaO-B2O3-SiO2系玻璃陶瓷性能研究

研究了碱金属氧化物对CaO-B2O3-SiO2(CBS)系玻璃陶瓷的软化析晶温度以及材料的烧结、介电等方面性能的影响。结果表明:对于添加双碱的CBS玻璃,随双碱金属离子半径增大软化温度呈升高趋势,而析晶峰值温度呈降低趋势。Na2O和K2O添加对于改善CBS系玻璃陶瓷烧结性能效果更好,试样内部晶粒分布均匀、结构致密。烧成试样主晶相均为CaSiO3,CaB2O4和石英。试样的介电常数和介电损耗随频率的增加而减小。随着测试温度的升高,试样的介电常数略有增加,而介电损耗呈降低趋势。     

SiO2-Fe2O3-Cr2O3-MnO2高温红外辐射节能涂料的制备及应用

以SiO2、Fe2O3、Cr2O3、MnO2为原料按比例混合,经固相高温烧结制备成基体粉料,再与粘结剂混合球磨制备出高温红外辐射节能涂料。通过XRD、半球点测试仪、红外辐射测量仪、纳米粒度测试仪对材料的微观结构和理化性能进行了表征,采用热震法对涂层的抗热震性能进行了研究。研究结果表明,随着平均粒径的减小,合成的SiO2-Fe2O3-Cr2O3-MnO2体系全波段红外辐射率有明显增大的趋势。当平均粒径达到2μm左右时,涂料全波段红外辐射率最高达到0.93。涂料的最高使用温度达1400℃以上,涂层的抗热震性能良好。此外,在燃气梭式干燥窑上使用该高温红外辐射节能涂料后,降低能耗15%左右,抗老化性能优良,使用一年后辐射率仍在0.90以上。     

SnP2O7中温固体电解质的制备和导电性能

用固相反应法制备了不同P/Sn物质的量比的SnP2O7,并研究了该电解质在120～260℃范围内的导电性能。XRD分析表明SnP2O7为立方结构。热重分析了电解质在中温范围内的稳定性。用交流阻抗谱测量了电解质电导率,电导率随着HPO3在电解质中的残余量的提高而提高。测试结果表明电解质中起导电作用的主要是HPO3,而SnP2O7主要起支撑作用。最大电导率是在200℃,P/Sn物质的量比为3.0时,干空气条件下为5.1×10-2S/cm,湿空气条件下为6.6×10-2S/cm。     

基于Al2O3纳米流体的槽式太阳能热发电集热器传热建模及性能分析

基于计算流体动力学中的有限体积法,研究了Al₂O₃/Syltherm800导热油纳米流体作为传热介质时槽式太阳能热发电集热器的性能,建立了真空管集热器的三维模型,进行了光学模拟和传热数值模拟,并通过实验进行了验证。在非均匀热流密度分布的情况下,研究了进口温度、进口流速等运行参数对采用纳米流体的槽式集热器传热性能的影响规律。结果表明:随着Al₂O₃体积分数的增加,槽式集热器的换热性能及热效率均有所提高;进口温度、进口流速等运行参数对集热器的传热性能影响很大,随着进口温度的上升和进口流速的减小,纳米流体对传热性能的影响程度逐渐增大。     

Hydrothermal synthesis and magnetic property of Cu3(OH)2V2O7·nH2O

Copper vanadium oxide hydroxide hydrate (Cu₃(OH)₂V₂O₇·nH₂O) nanoparticles with mean size of about 100 nm were successfully synthesized by a simple hydrothermal method. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectra, and Fourier transform infrared spectra (FTIR). The composition and purity of the as-synthesized Cu₃(OH)₂V₂O₇·nH₂O nanoparticles were characterized by Energy disperse spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The magnetic property of the as-synthesized Cu₃(OH)₂V₂O₇·nH₂O nanoparticles was characterized by vibrant sample magnetometer. Magnetic hysteresis curve indicate that the as-synthesized nanoparticles are of weak ferromagnetic property at room temperature.     

Synthesis of (Na2O,PbO)-Nb2O5, (Na2O,BaO)-Nb2O5, and (K2O,SrO)-Nb2O5 thin films using sol-gel method

Homogeneous pore-free Ba₂NaNb₅O₁₅, KSr₂Nb₅O₁₅, and 2·Na₂O-PbO-6·Nb₂O₅ thin films were fabricated on sapphire substrates using the sol-gel technique. By controlling the gelation and coating process, thickness of thin films fabricated was controllable from ~ 40 nm to ~ 10 μm. Synthesized thin films possessed highly preferred orientated microstructure. Another advantage of this method is the subsequent heat treatment temperature dramatically decreased compared with other methods. This increases stoichiometry control and makes the large scale fabrication more feasible and efficient.     

Dielectric, magnetic and spectroscopic properties of Li2O–WO3–P2O5 glass system with Ag2O as additive

Li₂O–WO₃–P₂O₅ glasses containing small concentrations of Ag₂O from 0 to 1 mol% were prepared. A number of studies viz., chemical durability, dielectric studies (constant ′, loss tan δ, a.c. conductivity σ_ac over a range of frequency and temperature), spectroscopic (infrared, optical absorption ESR spectra) and magnetic susceptibility studies of these glasses, have been carried out. The interesting variations observed in all these properties with the concentration of Ag⁺ ions have been analyzed in the light of different oxidation states and environment of tungsten ions in the glass network.     

Low-temperature syntheses in the system K2OAl2O3GeO2H2O

Four crystalline phases have been synthesized in the system K₂OAl₂O₃GeO₂H₂O from over 250 runs carried out at 90, 150 and 225°C: KH₃Ge₂O₆ (GC), KAlGeO₄ (GL), an unidentified phase, GM, and GH, the germanic analogue of phillipsite. No additional phase has been obtained from mixed KNa gels. Partial results on the effect of the initial water content on the crystallization are given.     

Conversion of V2O5·xH2O into orthorhombic V2O5 single-crystalline nanobelts

Orthorhombic V₂O₅ single-crystalline nanobelts have been synthesized by hydrothermal treating V₂O₅·xH₂O precipitate derived from aqueous solution of V₂O₅ and H₂O₂. The synthetic method is facile, fast, environmental friendly, and easy to scale up. The V₂O₅ single-crystalline nanobelts are 30-80 nm in width, 30-40 nm in thickness, and lengths up to several tens of micrometers. The V₂O₅·xH₂O precursor is crucial for the formation of orthorhombic V₂O₅ single-crystalline nanobelts. The influences of synthetic parameters, such as reaction time and reaction temperature, on the crystal structures and morphologies of the resulting products have been investigated. Time-dependent experiments show that V₂O₅·xH₂O are dehydrated gradually and converted into orthorhombic V₂O₅ single-crystalline nanobelts. High reaction temperature also favors the formation of orthorhombic V₂O₅ nanobelts.     

Bi2O3助熔剂对CaO-B2O3-SiO2/Al2O3玻璃陶瓷复合材料性能的影响

以CaO-B₂O₃-SiO₂(CBS)玻璃粉体和Al₂O₃陶瓷粉体为原料,通过在CBS与Al₂O₃的质量比固定为50:50的玻璃-陶瓷复合材料中添加适量的Bi₂O₃作为烧结助熔剂,探讨了Bi₂O₃助熔剂对CBS/Al₂O₃复合材料的烧结性能、介电性能、抗弯强度和热膨胀系数的影响规律.研究表明:Bi₂O₃助熔剂能通过降低CBS玻璃的转变温度和黏度促进CBS/Al₂O₃复合材料的致密化进程,于880 ℃下烧结即能获得结构较致密、气孔较少的CBS/Al₂O₃复合材料.然而,过量添加Bi₂O₃将使玻璃的黏度过低,从而恶化CBS/Al₂O₃复合材料的烧结性能、介电性能及抗弯强度.当Bi₂O₃的添加量为CBS/Al₂O₃复合材料的1.5wt%时,于880 ℃下烧结即能获得最为致密的CBS/Al₂O₃复合材料,密度为2.82 g·cm^-3,这一材料具有良好的介电性能(介电常数为7.21,介电损耗为1.06×10^-3),抗弯强度为190.34 MPa,0~300 ℃的热膨胀系数为3.52×10^-6 K^-1.     

Large-scale fabrication of H2(H2O)Nb2O6 and Nb2O5 hollow microspheres

Hollow micro-sized H₂(H₂O)Nb₂O₆ spheres constructed by nanocrystallites have been successfully synthesized via a bubble-template assisted hydrothermal process. In the reaction process, H₂O₂ acts as a bubble generator and plays a key role in the formation of the hollow structure. An in situ bubble-template mechanism has been proposed for the possible formation of the hollow structure. The spherelike assemblies of these H₂(H₂O)Nb₂O₆ nanoparticles have been transformed into their corresponding pseudohexagonal phase Nb₂O₅ through a moderate annealing dehydration process without destroying the hierarchical structure. Optical properties of the as-prepared hollow spheres were investigated. It is exciting that the absorption edge of the hollow Nb₂O₅ microspheres shifts about 18 nm to the violet compared with bulk powders in the UV/vis spectra, indicating its superior optical properties.     

TiAl多层膜焊接Cu-Al2O3异种材料接头性能研究

为探究热循环对陶瓷-铜接头性能的影响,采用Al-Ti纳米多层膜作为中间层材料焊接铜与陶瓷,并对接头进行分析。结果表明,接头力学性良好,整个焊接接头分为铜、扩散反应区、致密反应区以及陶瓷四个区域;经500次热循环试验后,连接区域面积缩小,扩散反应区出现空洞且整个接头扩散区变小,鱼骨状组织变粗大,剪切强度显著降低。     

Phases ε obtenues par decomposition des spinelles non-stoechiometriques dans les systemes Ga2O3-MgO,Al2O3-NiO,Al2O3-AlN et Al2O3-Li2O

In the systems Al₂O₃-AlN, Al₂O₃-NiO, Al₂O₃-Li₂O and Ga₂O₃-MgO, non-stoechiometric spinels, when decomposed at high temperatures, form an intermediate metastable phase ε. This phase has a one-dimensional periodic antiphase-domain structure. The antiphase boundaries are parallel to the (310) plane and the displacement vector is $\text{1}\text{4}$ [110] when referred to the spinel structure. Across each antiphase boundary, some octahedral and tetrahedral sites share faces instead of corners. In the case of ε_AlN, cationic vacancies occupy these sites; in the other cases, this is likely to go along with a segregation of the more charged ions.     

Y2O3与Gd2O3共掺杂SrZrO3热障涂层材料的热物理性能

采用固相反应法合成了5mol%Y2O3与5mol%Gd2O3共掺杂SrZrO3(Sr(Zr0.9Y0.05Gd0.05)O2.95,SZYG)粉末.采用X射线衍射(XRD)和差示扫描量热仪(DSC)分别研究了SZYG粉末在1450℃长期热处理后以及200~1400℃范围内的相稳定性.采用高温热膨胀仪测量了SZYG块材的热膨胀系数,结果表明:通过Y2O3与Gd2O3共掺杂改性可以明显抑制SrZrO3的相转变.在1000℃下SZYG块材的热导率是～1.36 W/(m.K),与SrZrO3和8YSZ块材相比降低~35%SZYG分别与8YSZ和Al2O3在1250℃热处理24 h表现出很好的化学相容性.