Theoretical prediction of ion conductivity in solid state HfO2

A theoretical prediction of ion conductivity for solid state HfO2 is carried out in analogy to ZrO2 based on the density functional calculation. Geometric and electronic structures of pure bulks exhibit similarity for the two materials. Negative formation enthalpy and negative vacancy formation energy are found for YSH (yttria-stabilized hafnia) and YSZ (yttria- stabilized zirconia), suggesting the stability of both materials. Low activation energies (below 0.7 eV) of diffusion are found in both materials, and YSH’s is a little higher than that of YSZ. In addition, for both HfO2 and ZrO2 , the supercells with native oxygen vacancies are also studied. The so-called defect states are observed in the supercells with neutral and +1 charge native vacancy but not in the +2 charge one. It can give an explanation to the relatively lower activation energies of yttria-doped oxides and +2 charge vacancy supercells. A brief discussion is presented to explain the different YSH ion conductivities in the experiment and obtained by us, and we attribute this to the different ion vibrations at different temperatures.     

ZrO2基固体电解质薄片水基凝胶注模低成本制备

本文采用水基凝胶注模制备高固相含量氧化钇稳定氧化锆薄片。研究了分散剂、pH值和固含量对水基料浆稳定性、粘度的影响,并优化了实验参数。最终,制备出100 mm×100 μm×100 μm的YSZ坯体薄片,通过SEM观察,密度和抗弯强度的测量,表明坯体结构比较均匀、致密。在1600℃×2 h烧结后,1000℃时的离子电导率可达0.155 S·cm～1。     

Fabrication of lanthanum doped yttria transparent ceramics

Yttria nanocrystalline powder doped with 9% lanthanum was synthesized by co-precipitation method using ammonia for pH adjusting. After calcinations, finer particles with narrow distribution and large surface area were obtained. After dry pressing, samples were sintered at 1500℃--1700℃ for 4 h in vacuum to produce transparent polycrystalline ceramics with uniform grains. Samples with 9 mol% lanthanum were transparent in visible light after being sintered at 1500℃ for 4 h. The grain sizes increased with lanthanum doping compared with those of pure yttria transparent ceramic sintered at the same conditions. Relative density of the transparent ceramic was 99.7%. The in-line transmittance was 73% at 580 nm wavelength after milling and polishing.     

肼对热分解法制氧化钇比表面积的影响

肼对热分解法制氧化钇比表面积的影响吴介达＊陆世鑫王振华王晔明（同济大学化学系上海２０００９２）（上海跃龙有色金属有限公司上海）关键词氧化钇，肼，比表面积１９９６－０９－２３收稿，１９９７－０４－１８修回上海市自然科学基金资助课题氧化钇是一种需求量大、...     

溶剂热合成一维纳米结构的氧化钇前驱体粉体及其研究

无机材料的溶剂热合成研究近些年得到飞速发展，在这里我们用溶剂热法来合成得到一维纳米结构的粉体。通过选择不同的有机溶剂来观察溶荆对产物形貌、结构等的影响。利用XRD、扫描电镜对产物的结构与形貌进行表征。     

电脉冲沉积铝化物及铝化物—Y2O3涂层

采用电脉冲沉积技术在20碳钢表面上获得了冶金结合的晶粒尺寸约为几十到几百纳米的铝化物和铝化物＋弥散Y2O3复合微晶涂层,600度空气中氧化100h的结果表明,电脉冲沉积获得的两种涂层均可显著地降低20碳钢的氧化速率并提高氧化层的抗剥落性能,用AFM,SEM,EDS和XRD对铝化物涂层及据氧化层进行了分析,并讨论了两种涂层提高抗氧化性能的作用机制。     

Ba0.95Ce0.9Y0.1O3-α固体氧化物燃料电池性能

以Ba0.95Ce0.9Y0.1O3-α为固体电解质,Pt为电极,组成氢-空气燃料电池,测定了该电池600～1000℃下电流-电压特性、电极极化特性和电解质中各电荷载流子(质子、氧离子、电子空穴)迁移数及其电导率。实验表明,该电池放电性能良好,能稳定地输出电能,1000℃时的最大输出电流密度为680mA.cm^-^2。正、负Pt电极极化特性很小,放电时的电压耗损主要由电解质电阻产生。在氢-空气燃料电池条件下,Ba0.95Ce0.9Y0.1O3-α显示混合离子(质子+氧离子)导电性。随着温度升高,质子迁移数减小而氧离子迁移数增大,当温度为780℃时,质子和氧离子迁移数相同(0.46),在低于780℃时,质子电导占优势,而在高于780℃时,氧离子电导占优势。     

Y2O3掺杂ZrO2对苯选择加氢制环己烯催化剂Ru-La-B/ZrO2性能的影响

用水热合成法制备了纳米Zr O2和Y2O3掺杂的Zr O2(Zr O2-Y),并考察了它们作载体对苯选择加氢制环己烯催化剂Ru-La-B/Zr O2性能的影响。结果表明,2种Zr O2具有相同微晶尺寸、织构性质和粒度分布。但Zr O2仅含有单斜相Zr O2,而Zr O2-Y不但含有单斜相Zr O2,还含有一部分四方相Zr O2。Y2O3掺杂影响Zr O2的组成和物相,进而影响用其制备催化剂的组成和物相。掺杂的Y2O3可以占据一部分不适宜苯加氢生成环己烯的活性位。因此,Zr O2-Y负载Ru-La-B催化剂活性明显低于Zr O2负载的,在低苯转化率下环己烯选择性前者比后者高。由于四方相Zr O2表面羟基比单斜相少,Zr O2-Y负载Ru-La-B催化剂的亲水性比Zr O2负载的差。环己烯不易从Zr O2-Y负载的催化剂表面脱附。当苯转化率高于52%时,Zr O2-Y负载的催化剂的环己烯选择性低于单斜相Zr O2负载的。Zr O2负载的Ru-La-B催化剂上20 min的环己烯收率达到了52.1%,而Zr O2-Y负载的环己烯收率仅45.2%。纳米单斜相Zr O2较适宜作苯选择加氢制环己烯Ru催化剂的载体。     

ICPMS测定高纯氧化钇中痕量稀土杂质的研究

研究了直接电感耦合等离子质谱（ＩＣＰＭＳ）测定９９．９９９％纯度氧化钇中稀土杂质的方法，详细探讨了仪器工作参数对稀土元素的测定的影响，对各种干扰现象进行了研究，并提出定量校正方法，实验表明，加入内标元素可有效地克服基体效应、接口效应和仪器工作参数漂移的影响。方法的检出限为０．００３～０．０２ｎｇ／ｍｌ，变异系数（ＣＶ％）为０．２％～５．４％，回收率为９０％～１１５％。适合９９．０％～９９．９９９％