烧结温度对钇掺杂氧化锌导电陶瓷局域电子密度和结构缺陷的影响

应用正电子湮没技术,对掺杂Y2O3的ZnO导电陶瓷烧结过程进行了研究,给出了烧结温度对导电特性、局域电子密度、结构缺陷的影响特征。研究发现:提高烧结温度,Zn填隙离子迅速迁移,ZnO导电陶瓷电阻率明显下降,同时产生大量微空洞缺陷。     

锂离子电池正极材料LiNiO2的制备及修饰

详细综述了锂离子电池正极材料锂镍氧的制备方法,探讨了不同离子对的掺杂改性作用和表面修饰对材料性能的影响.如果严格控制合成条件、优化合成工艺,可以合成近乎化学计量的LiNiO2.通过混合掺杂改性和表面修饰,可以制备出循环性能好、充放电容量大、热稳定性高的锂镍氧正极材料.     

液相法制备掺杂半导体纳米晶研究进展

掺杂即为有目的地将某些杂质原子掺入基体材料中,调控半导体材料能级结构以及空穴或电子的浓度,从而改变宿主半导体的电学、光学、磁学性能。纳米晶由于尺寸太小,存在"自清洁"、"自淬灭"、"自补偿"等效应,使得纳米晶的稳定掺杂及电子掺杂态的调控难以实现。本文综述了近年来掺杂半导体纳米晶的的液相制备方法以及过渡金属发光离子、磁性离子以及稀土离子掺杂的半导体纳米晶的光电性能及应用。并进一步讨论了掺杂纳米晶在未来面临的挑战和发展趋势。     

Y2O3与MgO复合掺杂ZrO2材料的电性能研究

利用交流复阻抗分析技术对Y2O3与 MgO复合掺杂ZrO2材料的电性能进行了研究.发现随着Y2O3掺入量的增加,参与跃迁的氧空位增多,并促进烧结体的密度提高,气孔率降低,使得晶粒边界的电阻减少,导致(ZrO2)1-x-y(YO1.5)x(MgO)y陶瓷电导率增大.烧结温度的提高也是增加 (ZrO2 )1-x-y(YO1.5)x(MgO)y陶瓷电导率的重要因素之一.     

sol-gel法制备B位掺杂铝酸镧红外辐射陶瓷材料

采用sol-gel法制备Fe、Fe-Ni离子B位掺杂的LaAlO3基红外辐射陶瓷材料,通过XRD、FTIR、SEM、IR-2、XPS等手段对掺杂试样进行表征分析。研究结果表明,掺杂后所得产物皆为钙钛矿结构复合氧化物,掺杂Fe后红外发射率有所提高但增加幅度较小,Fe-Ni共掺试样的红外辐射性能明显改善。当Fe3+掺杂量x=0.25时,在3~5μm波段的红外发射率从0.345提高到了0.821。红外发射率提高的物理机制在于:B位掺杂后存在产生氧空位和化学价变化两种补偿机制。化学价变化可产生Ni 3+Ni 2+和Fe3+Fe2+等小极化子,有助于电子从价带到导带的跃迁;随着氧空位浓度的增加,吸附氧比例增大,有利于提高材料在近中红外波段的吸收性能。因此,铝酸镧型材料作为炉窑的内衬材料可提高炉内辐射传热,具有广阔的应用前景。     

钇掺杂对Ce0.33Zr0.67O2储氧性能的影响

采用柠檬酸溶胶凝胶法制备了一系列钇掺杂的富锆铈锆复合氧化物Ce0.33YxZr0.67-xO2,并通过XRD,BET,OSC,XPS,in-situ CO-FTIR等测试,系统研究了钇掺杂后铈锆复合氧化物储放氧性能的变化规律及其影响因素。结果表明,钇离子能够进入铈锆晶格形成固溶体,并提高铈锆体系的结构热稳定性。对于新鲜样,钇掺杂可大幅提升Ce0.33Zr0.67O2材料的比表面积,提高单位质量铈锆材料的储氧能力;但老化后,钇掺杂样品的储氧性能随着掺杂量的增加而减小。通过XPS及原位红外吸附性能测试证实,钇在Ce0.33Zr0.67O2材料表面主要取代锆离子,其掺杂会降低样品的表面吸附能力,抑制铈的氧化还原反应,从而导致该体系储氧性能的下降。     

LnO2-δ-ZrO2(Ln=Ce,Tb,Pr)储氧材料的制备与结构

迄今为止,国际普遍使用的储氧材料主要是以具萤石四方结构CeO2-δ-ZrO2为基体掺杂Y2O3的固溶氧化物.为进一步提高储氧材料的储氧、催化、高温稳定性和抗老化性能,本研究采用 "超声膜扩散"法制备了(LnO2-δ)x-(ZrO2)1-x ( Ln = Ce,Pr,Tb)储氧材料.通过热重(TG)、微分扫描热分析(DSC)和XRD对其固溶过程和结构特征进行了研究.结果表明,(PrO2-δ)x-(ZrO2)1-x和(TbO2-δ)x-(ZrO2)1-x显示出具有(CeO2-δ)x-(ZrO2)1-x同样晶体结构,较后者更稳定的固溶体组织,为进行储氧催化等性能的研究提供了基础.     

(CoxFe1-x)2P@NCNTs催化剂的制备及其在酸性电解质中的氧还原反应

提高非贵金属催化剂氧还原反应(ORR)性能对实现质子交换膜燃料电池的大规模应用至关重要，我们通过简单的一锅法合成了氮掺杂碳纳米管包覆铁掺杂磷化钴纳米颗粒催化剂((Co_xFe_1-x)₂P@NCNTs)。研究发现掺入的Fe离子可促进电子转移，增强(Co_xFe_1-x)₂P与N掺杂碳纳米管之间的协同作用，间接调控氮掺杂碳材料中吡啶氮和缺陷位点的含量，从而提高Co₂P基催化剂在酸性电解质中的ORR催化性能。起始位点、半波电位和极限电流均远高于Co₂P@NCNTs,且具有更强的抗甲醇能力和稳定性。     

掺杂Y2O3的ZnO导电陶瓷正电子寿命谱研究

用正电子湮没技术,结合X射线衍射结构分析,对掺杂Y2O3的ZnO导电陶瓷烧结过程进行了研究,给出了掺杂含量、烧结温度和烧结时间对材料结构的影响特征,研究发现:Y2O3掺杂量增加,ZnO导电陶瓷材料完整性变差;烧结温度升高,ZnO陶瓷产生微空洞为主的缺陷;烧结时间增加,微空洞缺陷数目明显增加。同时对正电子湮没机制与ZnO陶瓷导电特性的关联进行了研究。     

掺杂Y2O3的ZnO导电陶瓷正电子寿命谱研究

用正电子湮没技术,结合X射线衍射结构分析,对掺杂Y2O3的ZnO导电陶瓷烧结过程进行了研究,给出了掺杂含量、烧结温度和烧结时间对材料结构的影响特征,研究发现Y2O3掺杂量增加,ZnO导电陶瓷材料完整性变差;烧结温度升高,ZnO陶瓷产生微空洞为主的缺陷;烧结时间增加,微空洞缺陷数目明显增加.同时对正电子湮没机制与ZnO陶瓷导电特性的关联进行了研究.     

锂离子电池聚合物基复合金属氧化物固态电解质研究进展

随着电动汽车的不断普及,锂离子电池（LIBs）的安全性备受关注。目前固态锂离子电池具有能量密度高和安全性好的优势,被认为是解决传统液态锂金属电池安全隐患和提高其循环性能的关键材料。然而,单一形式的固态电解质存在离子电导率低、界面阻抗大等问题,限制了固态锂离子电池的发展。近年来,基于无机填料与聚合物电解质的有机-无机复合电解质受到了广泛关注,有机-无机复合固态电解质兼有聚合物与无机填料的优点,一方面可以提高柔韧性,另一方面可以有效提高电池的机械性能。本文归纳总结了有机聚合物与无机金属氧化物复合固态电解质的不同类型,分析了基于不同聚合物与无机金属氧化物复合形成的有机-无机复合固态电解质对锂离子电池复合界面行为、离子电导率、电池机械性能的影响,并对复合固态电解质制备和应用过程中存在的问题和解决方法进行了梳理。最后对聚合物基复合金属氧化物固态电解质未来要重点解决的问题和发展方向进行了预测。     

Properties and Application of Double Alkali Earth Doped Ce0.9Ca0. 1 - xSrxO1.90

A series of solid solution material based on ceria, Ceo.9Cao.l-xSrsOi.90(x = 0, 0.04, 0.05, 0.06), were synthesized by a solid reaction method. Ceria doped with two alkali earth dements has cubic fluorite structure. The ionic conductivity of these materials at high temperature was studied by impedance spectra, and an increasing effect of ionic conductivity was found. A maximum conductivity is achievedwhen the effective ionic radius is near to the critical radius (0. 1106 nm). Some fuel cells were made using these materials as electrolyte. The output power and current of the SOFC with the electrolyte of double doped ceria are better than those of YSZ and single doped ceria, and the open-circuit-voltage of the double doped ceria is also higher than that of the single doped ones.     

Highly transparent ytterbium doped yttrium lanthanum oxide ceramics

To prepare ytterbium doped lanthania yttria nanopowder a method of laser evaporation of mixed oxides was used. After calcinations of the powder at 1200 °C a pure single-phase solid solution Yb3+:(LaxY1–x)2O3 was formed in the nanoparticles. Influence of lanthanum oxide as an isovalent additive on the yttria structure was investigated. The lanthanium ions were proved to be a good aid to sinter yttria ceramics doped with Yb3+ at moderate temperatures about 1650 °С. The ceramics with relative density higher than 99.99% and grain size about 40 μm were fabricated. Full transmittance of 1.8 mm thick Yb0.11La0.23Y1.66O3 ceramics reached 82.5% at 800 nm. This material could be a good gain medium for ytterbium high power pulse lasers.     

Study of Bi_2O_3-based Rare Earth Solid Electrolyte Used in Fuel Cell

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Electrical conduction and mass transfer in crystalline oxides

The electrical conductivity of oxides is closely related to the reducibility or oxidizability of their metals. The experimental results of the authors and reported data are used to explain the behavior of the electrical conductivity of solid oxides and its relation to mass transfer with allowance for the ionic structure of these oxides.     

Formation and Characterization of Li0.24 ＋ 2x La0.59-x Mx TiO3-LaPO4 （M = K, Na） System

Ionic conductingsolid materials has received con-siderable attention in the last few years due to theirpotential utilityin high energy batteries and other elec-trochemical devices . Several systems of lithium fastion conductors ,such as γ-Li3PO4-type sol…     

Cathode Materials for Solid Oxide Fuel Cells(SOFC)

A detailed overview has been given concerning the use of rare earth materials in cathode fabrica-tion of solid oxide fuel cells(SOFC).It is focused on the various synthesis methods of the perovskite-typemixed rare earth oxides and the physical and chemical properties of the materials for cathode application ofSOFC.Also discussed is the doping mechanism of the related materials.Documented investigations showthat lanthanide of transition metals,especially manganese,chromium doped with strontium are most advan-tageous for the application.The crystallography,defect structure,conductivity and thermal matching withthe electrolyte and high temperature stability of cathode in oxidative gases are particularly emphasized.     

Effect of TiO2‐content on Reduction of Iron Ore Agglomerates

The effect of titanium oxide on iron ore agglomerates is studied by the use of test sinter, test pellets and synthetic briquettes under laboratory conditions. Titanium favours secondary hematite rather than magnetite, which is the main phase in the sinter of Rautaruukki's Raahe plant. Additionally, the effects of sinter RDI and pellet LTD on the blast furnace process are evaluated using the test results of basket trials in LKAB's Experimental Blast Furnace. The effect of titanium in synthetic hematite is studied as hematite is reduced to magnetite in the RDI test. This occurrence causes deterioration in burden permeability. Synthetic titanium‐bearing iron oxides under controlled conditions are investigated at the University of Oulu. The effect of TiO₂, in solid solution in magnetite, on the magnetite to hematite oxidation is studied separately in order to simulate the final stage of the sintering process. In other experiments, hematite samples doped with various contents of TiO₂ are studied using thermogravimetry under a controlled gas atmosphere (CO/CO₂/H₂/N₂). The TiO₂ content of hematite has a clear effect on reduction degradation. Also increasing content of TiO₂ in solid solution in magnetite radically accelerates the oxidation rate. In the pilot tests, TiO₂ content has a similar negative effect on the reduction strength of both sinter and pellets     

WC-20%Co添加陶瓷颗粒ZrO2的试验研究

利用热等静压真空烧结工艺制备了4种不同含量ZrO 2(3Y)的WC-20 %Co硬质合金.利用光学、扫描电子显微镜(SEM)进行了微观组织观察,并对试样进行了硬度测试、抗弯强度、冲击韧性和耐磨性的力学性能测试,试验结果表明ZrO 2(3Y)在WC-20 %Co基体中呈球形,均匀分布在Co相和WC相中,添加了ZrO 2(3Y)的WC-20 %Co的硬质合金抗弯强度和冲击韧性明显提高,耐磨性能有明显改善,硬度指标变化不大.