Er2O3掺杂Gd2(Zr0.8Ti0.2)2O7陶瓷的物理性能

用固相反应法制备(Gd_1-xEr_x)₂(Zr_0.8Ti_0.2)₂O₇(摩尔分数x=0,0.2,0.4)陶瓷并测试其晶体结构、显微形貌和物理性能,研究了Er₂O₃掺杂的影响。结果表明,(Gd_1-xEr_x)₂(Zr_0.8Ti_0.2)₂O₇陶瓷具有立方烧绿石结构,显微结构致密,在室温至1200℃高温相的稳定性良好;Er³⁺掺杂降低了陶瓷材料的热导率和平均热膨胀系数,当x=0.2时,其1000℃的热导率最低(为1.26 W·m^-1·k^-1)。同时,Er³⁺掺杂还提高了这种材料的硬度和断裂韧性。     

Ge掺杂对TiO2-Nb2O5-CaCO3压敏陶瓷结构及性能的影响

TiO₂ 压敏电阻是一种典型的非线性电流-电压电子器件, 本文研究了Ge掺杂对TiO₂-Nb₂O₅-CaCO₃压敏陶瓷的非线性系数α和压敏电压E_B的影响。采用传统的球磨-成型-烧结方法成功制备Ge掺杂TiO₂-Nb₂O₅-CaCO₃压敏陶瓷, 用压敏直流参数仪测试样品的非线性系数α、压敏电压E_B和漏电流J_L等电学性质, 并根据相关公式计算样品平均势垒高度。XRD、XPS、SEM和STEM分析表明, Ge掺杂显著改变TiO₂-Nb₂O₅ -CaCO₃压敏陶瓷微结构, 提高非线性系数α和减小压敏电压E_B。当施主Nb₂O₅和受主CaCO₃掺杂浓度分别为0.5mol%时, 掺杂1.0mol% Ge的压敏陶瓷获得了最高的非线性系数和较低的压敏电压(α=10.6, E_B=8.7 V/mm), 明显优于不掺杂Ge的TiO₂-Nb₂O₅-CaCO₃压敏陶瓷。此外, Ge熔点较低, 作为烧结助剂可以降低陶瓷的烧结温度, TiO₂-Nb₂O₅-CaCO₃-Ge压敏陶瓷最佳烧结温度是1300℃。     

添加Bi2WO6对ZnO基压敏陶瓷电学性能的影响

用传统固相反应法研究了添加Bi₂WO₆(x=0%~9%,质量分数)对ZnO基压敏陶瓷的微观结构、压敏性能和介电性能的影响。结果表明：掺入适量的Bi₂WO₆能促进ZnO压敏陶瓷晶粒均匀生长、提高微观结构的均匀性、降低压敏场强和提高非线性系数;同时,Bi₂WO₆的添加可提高ZnO晶粒表面吸附氧的含量,从而提高界面态密度和势垒高度以及ZnO基压敏陶瓷的非线性特性。Bi₂WO₆的添加量为7%的ZnO基压敏陶瓷,其综合性能为：E_{1 mA}=263 V/mm,α=53,J_L=3.50 μA/cm²,φ_b=11.52 eV。     

稀土氧化物Pr2O3掺杂对高压ZnO压敏电阻性能的影响

采用低温固相化学反应法制备了Pr₂O₃掺杂的ZnO纳米复合粉体, 并用此粉体在不同烧结温度下制备了高压ZnO压敏电阻。采用X射线衍射、 比表面测试、 透射电镜、 扫描电镜等手段对制备的ZnO纳米复合粉体及高压ZnO压敏电阻进行了表征, 并与未掺杂ZnO压敏电阻进行了对比研究, 探讨了稀土氧化物Pr₂O₃掺杂对高压ZnO压敏电阻电性能的影响机制。结果表明: 较低的烧结温度(1030～1130 ℃)时, 掺杂的稀土氧化物Pr₂O₃偏析于ZnO晶界中, 有活化晶界、 促使晶粒生长的作用; 同时, Pr₂O₃掺杂导致1080 ℃烧结的ZnO压敏陶瓷体中晶体相互交织形成晶界织构, 比未掺杂的更均匀和致密, 这有助于高压ZnO压敏电阻晶界性能的改善, 从而提高其综合电性能。当烧结温度为1080 ℃时, Pr₂O₃掺杂的高压ZnO压敏电阻的综合电性能最佳: 电位梯度为864.39 V/mm, 非线性系数为28.75, 漏电流为35 μA。     

Al2O3掺杂BaTi0.85Sn0.15O3陶瓷的制备及性能表征

通过传统固相二次烧结法来制备x wt% Al₂O₃（x=0、1.0、1.5）/BaTi_0.85Sn_0.15O₃（BTS）陶瓷。研究了掺杂不同含量Al₂O₃对BTS陶瓷的微观结构、介电性能及挠曲电性能的影响。结果表明,掺杂Al₂O₃的BTS陶瓷不改变陶瓷的晶体结构,仍为标准钙钛矿结构晶型;Al₂O₃的掺入能够有效降低晶粒尺寸,具有明显的细晶作用。随着Al₂O₃含量的增大,Al₂O₃/BTS陶瓷的介电常数减小,介电损耗得到明显改善,居里峰逐渐宽化且向温度高的方向偏移。Al₂O₃/BTS陶瓷的挠曲电系数随着Al₂O₃含量的增加和测试环境温度的升高均减小。此外,Al₂O₃/BTS陶瓷的挠曲电系数和介电常数之间存在一种近线性关系,但当温度非常接近于居里温度时,这种线性关系减弱。     

多层陶瓷结构Al2O3-Fe2O3/3Y-TZP梯度复合陶瓷的制备及性能

为更好地实现口腔修复体的美学修复效果,采用掺杂不同含量Fe₂O₃（0.01wt%~0.09wt%）和Al₂O₃（0.1wt%）的3 mol% Y₂O₃稳定的ZrO₂（3Y-TZP）粉体为原料,经过铺粉、压制、烧结等工艺制得色度渐变的多层陶瓷结构Al₂O₃-Fe₂O₃/3Y-TZP梯度复合陶瓷。对该梯度复合陶瓷的色度分布、烧结性能和力学性能进行检测,同时研究了Fe₂O₃和Al₂O₃的掺杂对3Y-TZP陶瓷组织和性能的影响。结果表明,制得的Al₂O₃-Fe₂O₃/3Y-TZP梯度复合陶瓷色度由红黄向白色沿成分变化方向呈梯度变化,与天然牙齿色度分布规律一致;力学性能呈梯度变化并从无色端到有色端逐渐降低,但仍满足牙科使用需求（≥ 800 MPa）;在无色瓷层中掺杂微量Al₂O₃（0.1wt%）可以改善Al₂O₃-Fe₂O₃/3Y-TZP梯度复合陶瓷的烧结性能,避免在预烧结过程中发生开裂。微量Fe₂O₃和Al₂O₃的掺杂会促进其在烧结过程中的致密化及晶粒长大;微量Fe₂O₃（0.01wt%）和Al₂O₃（0.1wt%）的掺杂有助于提高3Y-TZP陶瓷的挠曲强度,然而随着Fe₂O₃掺杂量的继续增多（≤ 0.09wt%）挠曲强度降低。      

铈掺杂Ba0.1Sr0.9TiO3的改性研究

铈掺杂Ba0.1Sr0.9TiO3陶瓷有着较高的介电常数和较低的压敏电压,但其烧结温度高,烧结成功率低,非线性系数小。用ZnO和过量TiO2加以改性,研究表明:适量TiO2起到了烧结助剂的作用,可将样品的烧结温度降低到1325℃,提高了样品烧结率,钛与锶的最佳物质的量比为5∶3;ZnO作为受主掺杂剂将样品的非线性系数提高到10以上,降低了介电损耗,其最佳的掺杂量为0.7%(摩尔分数)。最后用扫描电镜分析了掺杂ZnO样品的微观形貌。     

ZnO含量对AgCuOIn2O3SnO2ZnO材料电接触性能的影响

实验采用原位反应合成法制备了4种ZnO含量不同的AgCuO(10)In₂O₃(2)SnO₂(2)ZnO(x),(x=0.5、1、1.5、1.8)电接触材料并制成电触头铆钉，通过XRD、SEM、JR04C触点测试机等测试手段，分析了ZnO含量对材料电接触性能的影响。结果表明：电流电压的同时增大，材料电弧侵蚀现象更为明显；ZnO含量对接触电阻、熔焊力、阳极损耗及材料转移有着不同规律的影响，ZnO含量为1.8%(质量分数)的触头具有相对稳定且较低的接触电阻，当ZnO含量为1.0%(质量分数)时平均熔焊力最低，随着ZnO含量的增大，阳极损耗及质量转移质量呈现先减小后增大的趋势，但ZnO含量对于燃弧能量的影响不明显；电弧侵蚀后的阳极表面形成凹坑，阴极表面形成凸峰，ZnO含量的不同，阳极表面侵蚀面积及侵蚀形貌略有不同。对比发现，添加一定含量的ZnO对于AgCuO(10)In₂O₃(2)SnO₂(2)材料的电接触性能有所提升。     

多孔Al2O3f/Al2O3复合材料研究进展

作为20世纪90年代兴起的一类连续陶瓷纤维增强陶瓷基复合材料,连续氧化铝纤维增韧氧化铝(Al₂O_3f/Al₂O₃)复合材料已经发展为与C_f/SiC、SiC_f/SiC等非氧化物复合材料并列的陶瓷基复合材料。以多孔基体实现基体裂纹偏转成为Al₂O_3f/Al₂O₃复合材料主要的增韧设计方法,形成的多孔Al₂O_3f/Al₂O₃复合材料具有优异的抗氧化性能和高温力学性能,可在高温富氧、富含水汽的中等载荷工况中长时服役,是未来重要的热结构材料。经过近30年的发展,多孔Al₂O_3f/Al₂O₃复合材料已被应用于航空发动机、燃气轮机等热端部件。本文综述了多孔Al₂O_3f...     

稀土Y元素掺杂对PrBaCo2O5+δ陶瓷热电性能影响

利用传统陶瓷烧结工艺制备出不同浓度稀土Y元素掺杂PrBaCo₂O_5+δ氧化物热电陶瓷,采用XRD和热电材料性能测试系统等设备研究了稀土Y元素掺杂对PrBaCo₂O₅氧化物热电陶瓷晶体结构、热电性能的影响。测试结果表明：Pr_1-xY_xBaCo₂O_5+δ热电陶瓷均为双层钙钛矿结构,没有形成新的杂相;在测试温度范围内,Pr_1-xY_xBaCo₂O_5+δ(x=0,0.25,0.5,0.75)热电陶瓷的Seebeck系数均为正值,表明该材料导电载流子为以空穴,为p型半导体;稀土Y元素掺杂可以明显提高Pr_1-xY_xBaCo₂O_5+δ热电陶瓷的电导率,与电导率相反,稀土元素Y掺杂的导致Pr_1-xY_xBaCo     

多元施主掺杂对直流ZnO压敏陶瓷结构与电气性能的影响EI北大核心CSCD

采用传统的陶瓷烧结工艺制备B_(2)O_(3),In_(2)O_(3),Al_(2)O_(3)多元施主掺杂的直流ZnO压敏陶瓷样品,考察不同掺杂比(0.1%~0.4%,摩尔分数)的B_(2)O_(3)对直流ZnO压敏陶瓷样品微观结构和电气性能的影响。利用X射线衍射仪、扫描电子显微镜、能量色散X射线光谱及数字源表等分别对样品的物相、微观形貌、成分及电性能进行表征。结果表明,多元施主掺杂剂(Al_(2)O_(3),In_(2)O_(3)和B_(2)O_(3))的共掺杂明显改善直流ZnO压敏陶瓷的综合性能,其中,Al_(3)+提高样品的电导率,降低样品的残压比;In^(3+)通过钉扎效应限制晶粒的生长,改善样品的电压梯度;B^(3+)的掺杂增加样品的表面态密度,提高势垒高度并有效抑制泄漏电流的增加。B_(2)O_(3)掺杂量为0.3%时,样品的综合性能最优:电压梯度为486 V/mm,泄漏电流密度为0.58μA/cm^(2),非线性系数为85,残压比为1.55。     

Influence of praseodymium oxide/cobalt oxide ratio on microstructure and electrical properties of zinc oxide varistor ceramics

The microstructure and electrical properties of varistor ceramics, which are composed of (99.5–x–y)ZnO+xPr₆O₁₁+yCoO+0.5Dy₂O₃ system, were investigated with Pr₆O₁₁/CoO mole ratio (x/y=0.5/0.5, 0.5/1.0, 1.0/0.5, 1.0/1.0) and sintering temperature. The density of varistor ceramics with Pr₆O₁₁=1.0 was almost constant with sintering temperature, whereas it was increased noticeably in Pr₆O₁₁=0.5. Increasing Pr₆O₁₁ content enhanced the densification for any CoO content and the density was greatly affected not by CoO content but by Pr₆O₁₁ content. The varistor ceramics with Pr₆O₁₁/CoO=0.5/1.0 exhibited a higher nonlinearity than any other composition ratios. In particular, the varistor ceramics sintered at 1350 °C. exhibited the best electrical properties, with nonlinear exponent of 37.8, leakage current of 7.6 μA, and dissipation factor of 0.059. It was found that Pr₆O₁₁/CoO ratio greatly affects various characteristics of varistor ceramics.     

Effect of V2O5 on the Sintering Behavior, Microstructure, and Electrical Properties of (Na/sub 0.5/K/sub 0.5/)NbO/sub 3/Ceramics

Well-sintered (Na_0.5K_0.5)NbO_3-x mol% V₂O₅ ceramics (abbreviated as NKN-V) with fine electrical properties were successfully prepared by conventional solid-state reaction through the careful control of processing conditions. The sintering behavior, phase structure, and electrical properties of the V₂O₅-doped NKN ceramics were investigated. Results show that when the V₂O₅ content is 0.6 mol%, the NKN ceramics attained the maximum density of 4.46 g/cm³ (about 98.9% of the theoretical density) at 1060degC, and therefore possessed enhanced electrical properties. But when the V₂O₅ content continued increasing, the density decreased. The secondary phase (Na₂V₆O₁₆) could be detected by XRD analysis in all samples except x = 0 mol%. The Curie temperature of the NKN-based materials was found to decrease with the increase of V₂O₅. The dielectric properties of NKN ceramics doped with 0.6 and 0.9 mol% V₂O₅ were better than that of pure NKN ceramics. In addition, annealing treatment was proved to be an effective technique for improving dielectric properties and reducing the leakage current density.     

复合添加剂的共沉淀法制备及ZnO压敏陶瓷研究

采用共沉淀法合成的复合添加剂粉体制备ZnO压敏陶瓷,用TG-DTA热分析沉淀物前驱体, 通过XRD、SEM、EDS和DLS表征复合粉体的物相、形貌、组成元素、粒度及其分布, 测试压敏陶瓷性能、并观察其结构.结果表明, 550℃煅烧前驱体生成各添加剂氧化物的混合物; 650℃煅烧1 h形成组成为(Bi_1.14Co_0.26Mn_0.29)(Sb_1.14Cr_0.57Ni_0.29)O_6.25焦绿石型复合添加剂粉体, 复合粉体平均粒径为0.26μm; 复合粉体制备的ZnO压敏陶瓷的电位梯度为330 V/mm、非线性系数为47、漏电流为5μA/cm², 电性能参数分别优于固相法混合添加剂粉体制备的压敏陶瓷, 这归因于复合粉体制备的压敏陶瓷具有更均匀的显微结构.     

Influence of the common varistor dopants (CoO, Cr2O3 and Nb2O5) on the structural properties of SnO2 ceramics

The influence of dopants commonly used in SnO₂ varistor ceramics, such as CoO, Cr₂O₃ or Nb₂O₅, on the structural properties of SnO₂ was investigated. Several SnO₂-based ceramics containing only one of the dopants were prepared and characterized. Spectroscopic investigations [visible, near infrared (IR) and IR region] were performed to obtain information about dopants valence states inside the ceramics, as well as about their influence on electronic structure of the material. Structural properties were investigated by X-ray diffraction analysis and mechanisms of dopant incorporation were proposed. Obtained results were confirmed with results of the electrical measurements. Microstructural changes in doped ceramics were investigated by scanning electron microscopy (SEM) analysis that showed great differences in densities, grain size, and morphology of the SnO₂ ceramics depending on type of dopants and their distribution.     

Effect of Sm2O3 dopant on microstructure and electrical properties of ZnO-based varistor ceramics

ZnO-based varistor ceramics doped with fixed Y₂O₃ and different Sm₂O₃ have been prepared by the conventional solid-state reaction route, and the phase composition, microstructure and electrical properties have been investigated by XRD, SEM and a V–I source/measure unit. The XRD analyses show the presence of primary phase ZnO and some minor secondary phases. Doping appropriate contents of Sm₂O₃ decrease the leakage current and enhance nonlinearity characteristics of ZnO-based varistor ceramics markedly. The varistor ceramics with 0.25 mol% Sm₂O₃ sintered at 1,125 °C for 1 h exhibit reasonable electrical properties with the breakdown field of 446.4 V/mm, the nonlinear coefficient of 65.8 and the leakage current of 2.36 μA/cm². The results illustrate that doping Y₂O₃ and Sm₂O₃ may be a promising route for the production of ZnO-based varistor ceramics with good electrical properties.     

Li2O-B2O3-SiO2玻璃相对BaAl2Si2O8结构及微波介电性能的影响

采用固相工艺制备BaAl₂Si₂O₈-xwt%Li₂O-B₂O₃-SiO₂(x=0, 0.1, 0.3, 0.5, 1.0, 2.0)陶瓷。探究不同含量的Li₂O-B₂O₃-SiO₂(LBS)玻璃相对BaAl₂Si₂O₈(BAS)陶瓷的烧结温度、结构及微波介电性能的影响。结果表明: LBS玻璃相可明显降低BAS陶瓷的烧结温度, 并促进BAS陶瓷晶粒长大和晶体结构由六方相转变为单斜相。当x=0.1时, 六方相即可全部转变为单斜相, 在0.1≤x≤2.0范围内, BAS陶瓷晶体结构均为单斜相。添加0.3wt%的LBS玻璃相可促进BAS样品密度、介电常数和品质因数增大, 谐振频率温度系数绝对值减小。在x=0.3, 烧结温度为1275 ℃时, 可获得具有较好品质因数的单斜钡长石, 其介电性能: ε_r=6.74, Q×f=34570 GHz, τ_f= -15.97×10 ^-6/℃。