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。     

Influence of rare-earth oxides on structure and crystallization properties of Bi2O3–B2O3 glass

Bi₂O₃·B₂O₃ glasses doped with rare-earth oxides (RE₂O₃) (RE³⁺ = La³⁺, Pr³⁺, Sm³⁺, Gd³⁺, Er³⁺ and Yb³⁺) were prepared by the melting–quenching method. The relationships between composition and properties were demonstrated by IR, DSC, XRD and SEM analysis. The results show that the network structure resembles that of undoped Bi₂O₃·B₂O₃ glass, composing of [BO₃], [BO₄] and [BiO₆] units. RE₂O₃ stabilizes the glass structure as a modifier. Transition temperature (T_g) increases linearly with cationic field strength (CFS) of RE³⁺. La₂O₃, Pr₂O₃, Sm₂O₃ and Gd₂O₃ are benefit to promote the formation of BiBO₃ crystal. When Er₂O₃ and Yb₂O₃ are introduced, respectively, the main crystal phase changes to Bi₆B₁₀O₂₄. Transparent surface crystallized samples are obtained by reheating at 460–540 °C for 5 h. In this case, needle like BiBO₃ crystal or rare-earth-doped BiBO₃ crystal (Pr_xBi_1−xBO₃ and Gd_xBi_1−xBO₃) are observed, which is promising for non-linear optical application.     

固体激光用Nd:Lu2O3透明陶瓷的制备和光学性能研究

Nd:Lu2O3材料由于具有高热导率、低声子能量和优异的光学特性而成为非常有前景的高功率固体激光器用的增益介质.但Lu2O3单晶的熔点超过2400℃,难以生长,而Lu2O3陶瓷既能在低温下制备,又具有与晶体相当的光学性质和激光性能从而备受关注.本研究制备了高透明的Nd:Lu2O3陶瓷并对其光学性质和激光性能进行探究.以...     

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。     

Cr~（3＋）离子掺杂对Al_2O_3粉末结构及发光性能影响

采用球磨法制备了不同浓度Cr_2O_3掺杂的Al_2O_3粉体,并在700℃、1200℃空气中退火2 h。1200℃退火后样品,除掺杂浓度为1.6%的样品中出现少量γ-Al_2O_3相外,其余样品相均为纯α-Al_2O_3。样品晶格常数随着Cr~（3＋）离子浓度的增加而增加。采用波长为579 nm的激发光源对佯品进行荧...     

Effect of La2O3 addition and O2 atmosphere on the electric properties of SnO2TiO2

The electric properties of (Sn, Ti)O₂ doped with 1.00 mol% CoO, 0.05 mol% Nb₂O₅ and x mol% La₂O₃ (0.25≤x≤1.00) have been studied. Sn_0.25Ti_0.75Co_0.01Nb_0.005 doped with 0.50 mol% La₂O₃ has a nonlinearity coefficient of 6. An increase in the concentration of La₂O₃ raised its resistivity, thereby altering the electric properties of the material. A thermal treatment in oxygen atmosphere increased the nonlinearity coefficient to a value of 9.     

五层纳米SiO2-Al2O3/聚酰亚胺复合薄膜的制备及性能

采用浸胶法制备了一系列SiO₂-Al₂O₃/聚酰亚胺（SiO₂-Al₂O₃/PI）五层耐电晕薄膜A_m A_n PA_n A_m,其中中间层（P）为纯PI薄膜,外层（A_m）、次外层（A_n）分别为SiO₂-Al₂O₃掺杂不同质量分数的纳米SiO₂-Al₂O₃/PI薄膜。采用TEM、FTIR、宽频介电谱仪、电导电流测试仪、耐电晕测试仪、介电强度测试仪和拉伸实验机对五层纳米复合PI耐电晕薄膜的微观结构、介电性能和力学性能进行了表征和测试。结果表明,SiO₂-Al₂O₃/PI复合薄膜掺杂层形成了分布均匀的有机/无机复合结构;SiO₂-Al₂O₃纳米粒子的保护作用是影响复合材料耐电晕性能的主要因素,复合薄膜A₃₂A₁₆PA₁₆A₃₂的耐电晕寿命最大,为23.4 h;外层掺杂量对五层SiO₂-Al₂O₃/PI复合材料的介电强度影响较大,复合薄膜A₂₀A₂₈PA₂₈A₂₀的介电强度最大,为302.3 kV/mm;通过对五层复合结构的设计,可以在兼顾材料力学性能的同时,提高其耐电晕寿命和介电强度。     

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。      

Optimization of spectroscopic properties of Yb-doped refractory sesquioxides: cubic Y2O3, Lu2O3 and monoclinic Gd2O3

Absorption and emission spectra are given for Yb³⁺-doped Y₂O₃, Lu₂O₃ and Gd₂O₃ at room temperature. Y₂O₃ and Lu₂O₃ as close cubic matrices, show Yb³⁺ similar spectra different of Yb³⁺ in Gd₂O₃ monoclinic structure. Here, we use a new method to study and optimize the main spectroscopic properties with only one concentration gradient sample. Finally, assignments of Yb³⁺ Stark levels and Raman vibrations in Y₂O₃, Lu₂O₃ and Gd₂O₃ single crystal are given.     

La2O3添加对MgAl2O4-CaAl4O7-CaAl12O19复合材料烧结行为的影响

为适应材料轻量化的发展需要,在1 400~1 600℃温度下开发了MgAl₂O₄-CaAl₄O₇-CaAl₁₂O₁₉（MA-CA₂-CA₆）复合材料,并考察了La₂O₃添加对该复合材料烧结行为、显微结构和力学性能的影响。结果表明,La₂O₃添加剂优先固溶到MA-CA₂-CA₆复合材料组成晶相CA₆中,促使CA₆相发生晶格畸变,有效抑制了CA₆晶粒沿基面的异常长大,其形貌由片状向等轴状趋势转变,促使MA-CA₂-CA₆复合材料制备过程中由于CA₆晶粒异常长大而导致的多孔网状显微结构得以有效消除,因此也极大地改善了Mg²⁺的扩散条件,在一定程度上间接促进了MA晶粒的发育,有效促进了MA-CA₂-CA₆复合材料的烧结。经1 200℃预烧、1 600℃保温2 h烧成后,当La₂O₃的添加量为4wt%时,MA-CA₂-CA₆复合材料试样的显气孔率由19.2%下降至6.1%,体积密度由2.78 g/cm³上升至3.18 g/cm³,制得了MA、CA₂、CA₆晶相呈现交织分布、显微结构致密、有利于其力学性能改善的La₂O₃/MA-CA₂-CA₆复合材料,经1 200℃预烧、-1 600℃保温2 h烧成后的4wt% La₂O₃添加试样,其冷态抗压强度由317 MPa增加到了501 MPa。     

Properties of thin In2O3 and SnO2 films prepared by corona spray pyrolysis, and a discussion of the spray pyrolysis process

Thin films of doped In₂O₃ and SnO₂ were prepared by the “corona spray pyrolysis” technique with a deposition efficiency of 80%. The electrical and optical properties of the films were determined. A transmission of 88% in the visible region and an IR reflection of more than 90% were the maximum values obtainable for a doped In₂O₃ film.

A detailed discussion of the physical and chemical processes that occur during spray pyrolysis is presented to aid the understanding of this coating technique.

A minimum temperature of about 350°C for the formation of In₂O₃ was empirically confirmed.

Furthermore the powdery precipitate obtained during deposition of In₂O₃ was clearly identified as polycrystalline In₂O₃ formed by a homogeneous reaction.     

不同晶型Fe2O3催化H2O2湿法脱硝的实验研究

研究了以α-Fe₂O₃、β-Fe₂O₃和γ-Fe₂O₃为催化剂的类Fenton试剂溶液氧化吸收NO的过程,分析了3种Fe₂O₃的晶相结构和表面性质对NO脱除效率的影响机理。脱硝性能测试结果表明：γ-Fe₂O₃的活性最好,在H₂O₂浓度为1.5 mol/L、催化剂浓度为20 mmol/L、pH值为5以及反应温度为55℃等条件下,γ-Fe₂O₃的脱硝率可达87.5%。机理研究表明：3种Fe₂O₃催化H₂O₂分解湿法脱除NO的反应发生在催化剂表面,反应过程中存在氧化还原循环,H₂O₂催化分解的主要产物是·OH。活性差异分析结果表明：Fe₂O₃的晶相结构和表面性质对NO的脱除效果具有显著的影响,γ-Fe₂O₃的活性最高是由于比表面积大、分散性高和表面的Fe²⁺含量更多,而β-Fe₂O₃的活性高于α-Fe₂O₃是由于表面的氧空位含量更多。     

Sol–gel synthesis and luminescence of unexpected microrod crystalline Ca5La5(SiO4)3(PO4)3O2:Dy phosphors employing different silicate sources

Ca₅La₅(SiO₄)₃(PO₄)₃O₂ doped with Dy³⁺ were synthesized by sol–gel technology with hybrid precursor employed four different silicate sources, 3-aminopropyl-trimethoxysilane (APMS), 3-aminopropyl-triethoxysilane (APES), 3-aminopropyl-methyl-diethoxysilane (APMES) and tetraethoxysilane (TEOS), respectively. The SEM diagraphs show that there exist some novel unexpected morphological structures of microrod owing to the crosslinking reagents than TEOS as silicate source for their amphipathy template effect. X-ray pictures confirm that Ca₅La₅(SiO₄)₃(PO₄)₃O₂:Dy³⁺ compound is formed by a pure apatitic phase. The Dy³⁺ ions could emit white light in Ca₅La₅(SiO₄)₃(PO₄)₃O₂ compound, and the ratio of Y/B is 1.1, when the Dy³⁺ doped concentration is 1.0 mol%.     

Preparation and optical properties of sol–gel derived Er-doped Al2O3–Ta2O5 films

Thin films of the system xAl₂O₃–(100 − x)Ta₂O₅–1Er₂O₃ were prepared by a sol–gel method and a dip-coating technique. The influences of the composition and the crystallization of the films on Er³⁺ optical properties were investigated. Results of X-ray diffraction indicated that the crystallization temperature of Ta₂O₅ increased from 800 to 1000 °C with increased values of x. In crystallized films, the intensities of the visible fluorescence and upconversion fluorescence tend to decrease with an increase in x values, due to the high phonon energy of Al₂O₃; the strongest fluorescence is observed in a crystallized film for x = 4 heat treated at 1000 °C. In amorphous films obtained by heat treatment at relatively low temperatures the Er³⁺ fluorescence could not be observed because strong fluorescence from organic residues remaining in the films thoroughly covered the Er³⁺ fluorescence. On the other hand, the Er³⁺ upconversion fluorescence in the amorphous films was observed to be stronger than that in the crystallized films. The strongest upconversion fluorescence is observed in an amorphous film for x = 75 heat treated at 800 °C.     

N2O5/HNO3硝化合成1,2,3,4-丁四醇四硝酸酯

以赤藓糖醇为原料,利用绿色硝化剂五氧化二氮（N₂O₅）在硝酸(HNO₃)介质中硝解制得1,2,3,4-丁四醇四硝酸酯（ETN）。与现有混酸法相比,该反应可在无硫酸(H₂SO₄)环境下进行,后处理简单,废酸污染小。试验探讨了投料比、反应温度和反应时间对ETN产率的影响,用扫描电镜SEM、红外光谱IR等对不同ETN晶体的形态进行了表征。结果表明,投料比m(赤藓糖醇):m(N₂O₅):V(HNO₃)=2.5 g :4.0 g :20.0 mL、反应温度为20 ℃、反应时间为2 h时,ETN的产率最高,达76.6%。同时,3种不同晶体形态的ETN具有相同的特征峰。     

Frequency dependent electrical conductivity and dielectric relaxation behavior in amorphous (90V2O5–10Bi2O3) oxide semiconductors doped with SrTiO3

We report on the experimental results of frequency dependent a.c. conductivity and dielectric constant of SrTiO₃ doped 90V₂O₅–10Bi₂O₃ semiconducting oxide glasses for wide ranges of frequency (500–10⁴ Hz) and temperature (80–400 K). These glasses show very large dielectric constants (10²–10⁴) compared with that of the pure base glass (≈10²) without SrTiO₃ and exhibit Debye-type dielectric relaxation behavior. The increase in dielectric constant is considered to be due to the formation of microcrystals of SrTiO₃ and TiO₂ in the glass matrix. These glasses are n-type semiconductors as observed from the measurements of the thermoelectric power. Unlike many vanadate glasses, Long's overlapping large polaron tunnelling (OLPT) model is found to be most appropriate for fitting the experimental conductivity data, while for the undoped V₂O₅–Bi₂O₃ glasses, correlated barrier hopping conduction mechanism is valid. This is due to the change of glass network structure caused by doping base glass with SrTiO₃. The power law behavior (σ_ac=A(ω^s) with s<1) is, however, followed by both the doped and undoped glassy systems. The model parameters calculated are reasonable and consistent with the change of concentrations (x).     

Ni2O3对C3S形成过程的影响及其固溶效应

C3S是水泥熟料中最重要的矿物,杂质离子固溶进入C3S晶格并促进其单斜型或三方型稳定存在,研究离子在C3S中的固溶作用机理,能更深入了解阿利特的微结构及性质。利用化学分析、XRD、DTA及相图分析,研究Ni2O3对C3S形成过程的影响及其固化效应。结果表明:Ni2O3主要以+2价的形式在CaO-Si O2二元体系中存在,因其优先与Si O2反应形成固溶体,f-CaO随Ni2O3掺量递增而增大;当Ni2O3掺量大于其CaO-Si O2二元体系固溶极限时,f-CaO变化趋势呈相反趋势,且促进C3S形成效应明显。通过最小二乘法及Ni2O3固溶度的精确界定,可推导出Ni2O3在C3S中的固溶反应分子式为:(Ca3-0.53xNi0.53x)(Si1-0.47xNi0.47x)O5(x=0.0442)。     

MgAl2O4:Mg荧光粉的合成及其发光性能

用超声辅助聚丙烯酰胺凝胶法合成了MgAl₂O₄:Mg荧光粉。在MgAl₂O₄体系中引入的Mg金属颗粒抑制了MgAl₂O₄相的形成,在900℃及以上的温度烧结MgAl₂O₄:Mg干凝胶粉末,镁颗粒氧化成MgO。Mg金属颗粒的引入使MgAl₂O₄:Mg荧光粉的形貌由细小的纳米颗粒变为方便面型;MgAl₂O₄:Mg荧光粉的颜色由在600℃烧结时的暗棕色变为在800℃烧结时的白色,在1000℃烧结时白色变暗。随着烧结温度的提高MgAl₂O₄:Mg荧光粉的能带先增大后略微减小。引入镁颗粒使荧光光谱中位于395和425 nm的两个荧光峰淬灭,在650、656和680 nm出现三个新的荧光发射峰,且随着烧结温度的提高发光强度减弱。金属颗粒的表面等离子体共振导致MgAl₂O₄主晶格荧光淬灭,缺陷能级使MgAl₂O₄:Mg荧光粉产生了新的荧光发射峰。     

Tb1-xDyxFe2-y-BaTi0.99Mn0.01O3+δ层状复合材料的低频磁电耦合

利用弹性力学模型,推导了低频下磁致伸缩-压电双层复合材料中磁电电压系数的表达式,计算了Tb_1-x Dy_x-Fe_2-y-BaTiO₃层状复合材料中的横向磁电耦合。采用溶胶-凝胶法制备1.0%（摩尔分数）Mn掺杂BaTiO₃（BaTi_0.99Mn_0.01O_3+δ）压电陶瓷片。将Mn掺杂BaTiO₃与Tb_1-xDy_xFe_2-y 胶合制成双层和三层复合材料,研究了复合材料在低频下的横向磁电效应。XRD和DSC分析结果表明,室温下Mn掺杂BaTiO₃保持了其四方钙钛矿结构,降低了BaTiO₃的居里点和相变潜热。在约33 kA/m偏置磁场下,Tb_1-xDy_xFe_2-y-BaTi_0.99Mn_0.01O_3+δ 和Tb_1-xDy_xFe_2-y-BaTi_0.99Mn_0.01O_3+δ-Tb_1-xDy_xFe_2-y 的横向磁电耦合峰值分别为529.4 mV/A和1659.5 mV/A,分别是Tb_1-xDy_xFe_2-y-BaTiO₃和Tb_1-xDy_xFe_2-y-BaTiO₃-Tb_1-xDy_xFe_2-y 的1.48和1.45倍。三层复合材料的横向磁电电压系数约是同类双层的3倍多。     

Low-temperature synthesis of nanocrystalline ZnGa2O4:Tb phosphors via the Pechini method

The synthesis of trivalent terbium doped ZnGa₂O₄ nanosized new phosphors by the Pechini method was reported. Well-crystallized ZnGa₂O₄:Tb³⁺ phosphors were obtained at low-temperature about 550 °C. The phosphors formed porous agglomerates which consist of spherical nanocrystallites with a uniform size at about 30 nm. The photoluminescence of the phosphors included both the luminescence of ZnGa₂O₄ host and characteristic emission of Tb³⁺, and the excitation spectra showed an energy transfer from the host lattice to the activator. The Tb³⁺ emission from the phosphors prepared by the Pechini process was more intensive than that of phosphors by solid-state reaction process.