掺杂Sb2O3的SnO2基陶瓷的SPS制备及性能研究

采用放电等离子烧结技术(SPS)制备了掺Sb2O3的SnO2基陶瓷.研究了烧结温度及Sb2O3的含量对SnO2基陶瓷的密度、物相、结构和电学性能的影响.研究袭明:随着烧结温度的提高,SnO2基陶瓷的相对密度逐渐增大,室温电阻率璧先减小后增大的趋势;随着Sb2O3掺杂量的增加,样品的相对密度呈先增加后减小的趋势,室温电阻...     

La2O3掺杂对SnO2基陶瓷致密化与力学性能的影响

以La2O3作掺杂剂制得SnO2基陶瓷.运用XRD和SEM对SnO2基陶瓷的显微结构进行了表征,并测试了SnO2基陶瓷的体积密度、维式硬度、抗弯强度及断裂韧性.结果表明,在一定的掺杂范围内, La2O3的引入能明显改善SnO2基陶瓷的力学性能.同时,La2O3的加入可促进SnO2晶相的形成和生长,对SnO2基陶瓷的致密化起到了良好的作用.     

导电纳米颗粒对Sb:SnO2薄膜性能影响研究

采用水热晶化法,通过控制水热反应条件、溶液的浓度以及矿化剂的种类等因素,制备出分散性及导电性良好的SnO2纳米颗粒.采用溶胶-凝胶浸渍镀膜的方法制备Sb掺杂SnO2薄膜,在镀膜溶液的配制过程中引入SnO2纳米颗粒悬浮液,经陈化后最终得到镀膜溶液.采用van der Pauw法、UV/VIS分光光度计以及Fourier变换红外光谱仪研究和分析了添加纳米颗粒对膜层导电性能、光学性能以及膜层结构的影响;采用场发射扫描电镜研究了膜层的表面形貌.结果表明导电纳米颗粒的加入可有效提高膜层的导电性能,当SnO2纳米颗粒添加质量分数为10%时,膜层的电阻率为6.5×10…3Ω·cm;添加和未添加纳米颗粒的膜层的可见光透过率均为85%.纳米颗粒参与了溶胶-凝胶制备薄膜网络的形成,提高了膜层结构的连续性,从而使膜层具有较好的导电性能和光学性能.     

氧化锌-氧化锑复合掺杂二氧化锡基陶瓷的制备与电学性能

用无压烧结技术制备氧化锌(ZnO),氧化锑(Sb2O3)及ZnO-Sb2O3掺杂的氧化锡(SnO2)基陶瓷材料.用Archimedes排水法测定样品的相对密度(ρr).用van der Pauw 法测量SnO2基陶瓷材料的电阻率(R).用扫描电镜测试研究SnO2基陶瓷材料的显微结构、晶体结构,并分析材料的结构与性能的内在联系.研究表明:ZnO作为烧结助剂能显著地提高材料的烧结性能,材料的?r随ZnO掺量的增加先升高后降低,当ZnO的掺量(摩尔分数,下同)为1.0%时,样品的ρr最佳.材料的ρr随Sb2O3的增加而逐渐降低,R随Sb2O3的增加呈现出先降低后升高再降低的变化趋势.Sb2O3的掺量为0.5%时,ρr与R均较好;1.0%ZnO-0.5%Sb2O3的复合掺杂,在1 400℃无压烧结即可得到ρr为97%、室温R为0.1099μ·cm的致密SnO2基导电陶瓷材料.     

偶联剂表面改性Sb2O3的研究

研究了不同偶联剂表面改性Sb2O3的改性效果和条件,结果发现钛酸酯偶联剂NDZ-101的改性效果最佳,其最佳用量为1．0％与理论计算值相当;当改性时间大于30min,改性温度大于60℃,改性效果趋于稳定。     

热处理温度对Sb:SnO2导电粉结构和性能的影响

SnO2超细粉用作透明导电膜和导电涂料具有广阔的应用前景.以SnCl4·5H2O和SbCl3为原料,采用共沉淀法制得了纳米级的SnO2超细粉.运用差热-失重分析(DSC-TG)、X射线衍射(XRD)、透射电镜(TEM)和紫外光谱分析(UV)等观测手段对微粉末进行了表征,比较系统地研究了热处理温度对粉末颗粒度和电阻的影响规律,探讨了Sb:SnO2导电粉的显色特性.     

Sb2O3对ZnO基陶瓷性能的影响

本文主要报道Ｓｂ２Ｏ３杂质对ＺｎＯ基陶瓷性能的影响。在ＺｎＯ基陶瓷中添加Ｓｂ２Ｏ３杂质可以改善此种瓷的压敏性和介电性。     

Ti/SnO_2+Sb_2O_3+MnO_2/PbO_2阳极的制备及其性能

用热分解和电沉积联合方法制备了Ｔｉ／ＳｎＯ２＋Ｓｂ２Ｏ３＋ＭｎＯ２／ＰｂＯ２阳极．对该类电极进行了ＥＤＳ、ＳＥＭ、ＸＲＤ研究．测定了电极在１ｍｏｌ／ＬＨ２ＳＯ４溶液中的使用寿命和动力学参数．考察了其作为阳极用于含酚废水处理时的性能．结果表明，所制备电极在硫酸溶液中具有优良的电催化活性和电化学稳定性．     

Enhanced high temperature microwave absorption of La0.9Sr0.1MnO3/MgAl2O4 composite ceramics based on controllable electrical conductivity

The high temperature microwave absorbing efficiency (HTMAE) of xLa_0.9Sr_0.1MnO₃/(1 − x)MgAl₂O₄ composite ceramics was investigated by studying the crystal structure, electrical conductivity, and permittivity. The crystal structure of La_0.9Sr_0.1MnO₃ and MgAl₂O₄ were maintained, but the Mn³⁺ and Al³⁺ ions were exchanged with each other through doping. The conductivity and permittivity of the composite ceramics increased with the increase of La_0.9Sr_0.1MnO₃ content and test temperature. When x = 0.36, the electrical conductivity in La_0.9Sr_0.1MnO₃ significantly enhanced the microwave polarization of the composite ceramics at high temperature. According to transmission/reflection modelling, the composite ceramics with x = 0.24 showed excellent HTMAE near the optimal thickness of 1.8 mm. Although the optimal thickness of the composite with x = 0.36 was reduced to 1.1 mm, the HTMAE was seriously lessened due to an impedance mismatch. xLa_0.9Sr_0.1MnO₃/(1 − x)MgAl₂O₄ are promising as thin and efficient microwave absorbing materials at high temperatures and the microwave permittivity can be further enhanced by adjusting the conductivity of La_0.9Sr_0.1MnO₃.     

Densification behaviors of Al2O3 ceramics during flash sintering

The densification behaviors of MgO-doped-Al₂O₃ ceramics in the flashing stage and the steady stage were investigated using the classic kinetic model. The results show that the most densification of MgO-doped Al₂O₃ was completed during the flashing stage. The densification mechanism transferred from particle rearrangement resulted from Columbic force among particles under the effect of electrical field in the flashing stage to the lattice diffusion in the steady stage. Therefore, the densification rate in the steady stage dramatically decreased. Additionally, the estimated densification activation energy in the steady stage of flash sintering is 396 kJ/mol, much lower than the activation densification of lattice diffusion measured from conventional sintering, likely due to the effect of electric field/current-induced point defects on the diffusion.     

Enhancement of grain growth and electrical conductivity of La0.8Sr0.2MnO3 ceramics by microwave irradiation

We studied crystallization, grain growth and electric properties of La_0.8Sr_0.2MnO₃ (LSM) ceramics which were produced using the microwave-treatment. While co-precipitated nanoparticles remain mainly amorphous, the microwave irradiated particles are crystallized into LSM and La₂Mn₂O₇ at 550 °C, due to higher dielectric polarizability of La. This, in turn, decreases the amount of the second phase La₂O₃ in calcined powder and promotes the growth of perovskite grains during sintering at 1400 °C. Larger grains of LSM ceramics lower the activation energy of small polaron hopping from 0.35 eV to 0.24 eV and increases high-temperature electric conductivity. In addition, high crystallinity of LSM ceramics from the microwave-treatment suppresses a chemical reaction with ZrO₂ and NiO in a temperature range of 900 – 1100 °C under oxidizing and reducing ambiances. These results show that LSM ceramics from the microwave-assisted reaction meet requirements for an interconnect layer for solid oxide electrolysis cells.     

Influence of Bi2O3/TiO2, Sb2O3 and Cr2O3 doping on low-voltage varistor ceramics

The influence of the amount of Bi₂O₃ and TiO₂ additions at a TiO₂/Bi₂O₃ ratio of 1, as well as Sb₂O₃ and/or Cr₂O₃ doping, on the microstructural development and electrical properties of varistor ceramics in the ZnO–Bi₂O₃–TiO₂–Co₃O₄–Mn₂O₃ system was investigated. In samples with a low level of Bi₂O₃ and TiO₂ (0·3 mol%) and therefore small amount of liquid phase, exaggerated growth of the ZnO grains results in high microstructural inhomogeneity. Co-doping with Sb₂O₃ significantly changes the phase composition of TiO₂ doped low-voltage varistor ceramics. The Bi₃Zn₂Sb₃O₁₁ type pyrochlore phase forms at the expense of the γ-Bi₂O₃ and Bi₄Ti₃O₁₂ phases and decreases the amount of liquid phase in the early stages of sintering. Already small amounts of Sb₂O₃ and/or Cr₂O₃ added to a TiO₂ doped low-voltage varistor ceramics limit ZnO grain growth and increase the threshold voltage V_T of the samples.     

Structure and electrical conductivity of Li2O-B2O3 glasses

The temperature-concentration dependence of the electrical conductivity of Li₂O-B₂O₃ glasses in the temperature range of ～180–310°C has been studied. For pure boron anhydride, the dependence logσ = f([1/T]) is linear, whereas for glasses with ～2 mol % ≤ [Li₂O] < ～10 mol %, similar curves are kinked. At higher Li₂O concentration the kinks disappear. Occurrence of kinks is attributed to variation of essence of current carriers from proton pattern for B₂O₃ to mixed proton-ion pattern for low-alkali glasses. Conductivity of glasses at [Li₂O] ≥ 20 mol % is stipulated by the formation of a continuous sublattice of polar structuralchemical entities (entities) [BO_4/2]^?Li⁺ and the migration of lithium ions.     

TiN含量对TiN-Al2O3复合材料力学性能及导电性能的影响

以纯度(质量分数)均为99%的微米级TiN和α-Al2O3粉体为原料,采用湿法球磨混合5h制备了TiN体积分数分别为0、10%、20%、30%和40%的TiN-Al2O3复合粉体。将复合粉体压制成型,在200℃干燥12h,通过热压炉在pN2=-0.098MPa条件下于1800℃保温3h烧结得到TiN-Al2O3复合材料,并研究了微米级TiN含量对TiN-Al2O3材料力学性能和导电性能的影响。结果表明:随着TiN含量的增加,复合材料的烧结性能和力学性能不断提高,电阻率不断下降。TiN含量为40%(体积分数)时,材料的抗弯强度498MPa,断裂韧性4.285MPa·m1/2,电阻率1.34×10-3Ω·cm;材料的导电性能符合渗流理论,其渗流阈值Vc=17.24%,这与试验结果一致。而显微结构分析表明:TiN颗粒主要分布在Al2O3晶界处,晶粒细小,它们相互交织在一起形成网络,起到了抑制Al2O3晶粒长大和增韧补强作用,提高了材料的力学性能。