Cr掺杂Ba0.5Sr0.5Co0.8Fe0.1Cr0.1O3-δ钙钛矿型膜的透氧性能研究

采用固相反应法合成了钙钛矿型Ba0.5Sr0.5Co0.8Fe0.2-xCrxO3-δ(x=0.00,0.10)透氧膜粉体。利用XRD和SEM研究了Ba0.5Sr0.5Co0.8Fe0.2-xCrxO3-δ(x=0.00,0.10)的晶体结构和烧结性能,考察了在700~850℃范围内Ba0.5Sr0.5Co0.8Fe0.2-xCrxO3-δ(x=0.00,0.10)膜片的氧渗透性能。结果表明,它们均显示出优良的透氧性能,850℃时的透氧量分别为1.05mL/(min.cm2)、0.85mL/(min.cm2)。透氧稳定性的研究表明,Cr掺杂Ba0.5Sr0.5-Co0.8Fe0.1Cr0.1O3-δ在800℃时显示出较高的稳定性,证实用Cr离子部分取代Ba0.5Sr0.5Co0.8Fe0.2O3-δ的Fe离子能明显提高钙钛矿的结构稳定性。     

(Ba1-xSrx)La4Ti4O15（x=0.8～0.95）陶瓷的微结构及微波介电性能研究

采用固相反应法制备了(Ba1-xSrx)La4Ti4O15(x=0.8~0.95)复合体系微波介质陶瓷,并对其进行物相组成、晶体结构分析以及微波介电性能的研究.研究结果表明,(Ba1-xSrx)La4Ti4O15陶瓷主晶相为SrLa4Ti4O15,并伴随有第二相SrLa8Ti9O15.SEM观察表明,Ba0.2Sr0.8La4Ti4O15陶瓷内部微观结构致密,晶粒尺寸在10~20μm之间,晶界清晰.随着x值逐渐增大,(Ba1-xSrx)La4Ti4O15陶瓷中晶粒形态发生变化,气孔增多.在x=0.8时,(Ba1-xSrx)La4Ti4O15陶瓷具有优良的微波介电性能,即εr=40.86,Q×f≈62806 GHz,τf=20×10 6/℃.随着Ba2+的含量逐渐增加,该陶瓷的介电常数εr单调上升,品质因子Q×f值增加,说明适量的Ba2+替代Sr2+能改善陶瓷的微波介电性能.     

溶胶凝胶法合成La0.5Sr0.5Co0.8Mn0.2O3-δ钙钛矿及其催化性质

采用溶胶凝胶煅烧法合成了La0.5 Sr0.5 Co0.8 Mn0.2 O3-δ纳米粉,通过X射线衍射、电子显微镜、X射线光电子能谱和碘定量滴定等测试方法对合成物进行了表征,并以四溴双酚A为模型污染物,考察其催化性能.结果表明,合成的纳米La0.5 Sr0.5 Co0.8 Mn0.2 O3-δ具有钙钛矿R-3c结构,平均晶粒尺寸为40～70 nm.与通氮气煅烧的样品相比,弱氧化煅烧样品的非化学计量氧浓度适中,钙钛矿结构中B位离子平均价态相对较稳定,其催化性能较强且相对较稳定,可再生循环使用四次.     

La0.6M0.4Fe0.8Cr0.2O3-δ(M=Ca、Sr、Ba)的制备表征及电性能

采用甘氨酸-硝酸盐法(GNP)制备了纳米尺寸的La0.6M0.4Fe0.8Cr0.2O3-δ(M=Ca、Sr、Ba)系列粉体.BET测试表明,合成粉体的比表面积＞20 m2·g-1;XRD结果显示,GNP法合成粉体在燃烧阶段物相已初步形成,La0.6Ca0.4Fe0.8Cr0.2O3-δ(LCFC)初粉经850℃热处理2h即转变为简单立方钙钛矿结构的纯相产物,1100℃下烧结体的相对密度即达95%,La0.6Sr0.4Fe0.8Cr0.2O3-δ(LSFC)、La0.6Ba0.4Fe0.8Cr0.2O3-δ(LBFC)初粉为双相结构,两者在低温段的烧结活性较LCFC差,1300℃以上相对密度接近95%.四端子法电导测试表明,掺杂样品的电导率较LaFeO3高2个数量级以上,700℃以下三者的电导率随温度的变化符合小极化子导电机理;800℃下LCFC的电导率＞50 S·cm-1,预示其可能成为IT-SOFC有实际应用前景的阴极材料.     

掺杂Fe3+对高电压正极材料LiNi0.5Mn1.5O4结构和性能的影响

以Li2CO3、MnO2、NiO、FeC2O4·2H2O为原料,用高温固相法合成了尖晶石结构的LiNi0.5Mn1.5O4/LiNi0.5Mn1.45Fe0.05O4锂离子电池正极材料;并对合成的样品进行XRD、SEM及电化学性能测试。结果表明:引入Fe3+可以提高材料的结构稳定性,并且改善了材料的导电性,一定程度上减缓材料的容量衰减,LiNi0.5Mn1.45Fe0.05O4表现出较好的电化学性能,0.2C倍率下经20次充放电循环,未掺杂样品与掺杂样品的放电比容量分别为115.4mAh/g和120.1mAh/g,容量保持率由92.1%提高到96.5%。     

LnBaCo2O5+δ(Ln=Gd,Nd,Sm,Pr)-Ba0.5Sr0.5Co0.8Fe0.2O3-δ双相混合导体透氧膜的制备及性能测试

用固相反应法制备了LnBaCo2O5+δ(Ln=Gd,Nd,Sm,Pr)-Ba0.5Sr0.5Co0.8Fe0.2O3-δ(质量比为1:1)4种双相混合导体膜.通过XRD分析可知,除了PrBaCo2O5+δ和Ba0.5Sr0.5Co0.8Fe0.2O3-δ(BSCF)复合时发生明显反应外,其它3种复合膜在复合过程中均显示了良好的化学兼容性.4种双相膜在850℃时透氧率最高的是NdBa-(Co2O5+δ-Ba0.5Sr0.5Co0.8Fe0.2O3-δ膜(约为0.28mL/(cm2·min)).     

中温固体氧化物燃料电池阴极材料Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ的制备与性能研究

采用固相法合成Ba1-x Srx Co0.7Fe0.2Nb0.1O3-δ(x=0、0.1、0.2、0.3、0.4)阴极材料。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构和微观形貌进行了表征。XRD测试结果表明Ba1-x Srx Co0.7Fe0.2Nb0.1O3-δ样品经1000℃,烧结10 h后形成了立方钙钛矿结构。从样品的电镜照片看出样品具有均匀的孔隙率,电解质(Ce0.85Sm0.15O1.925)-阴极(Ba1-x Srx Co0.7Fe0.2Nb0.1O3-δ)之间的界面结合良好。电化学交流阻抗测试结果表明Ba1-x Srx Co0.7Fe0.2Nb0.1O3-δ中掺入Sr可以明显地降低阴极的极化电阻,随着Sr含量的增多,阴极的界面极化电阻(RP)先减少后增大,当Sr的含量x为0.2时Rp值最小。以Ce0.85Sm0.15O1.925(SDC)电解质为支撑体,Ni0.9Cu0.1-SDC为阳极,Ba0.8Sr0.2Co0.7Fe0.2Nb0.1O3-δ为阴极的单电池的最大功率密度在600℃时达到155 mW/cm2。实验结果表明Ba0.8Sr0.2Co0.7Fe0.2Nb0.1O3-δ材料是一种电化学性能较为优良的中温固体氧化物燃料电池阴极材料。     

BST/BZT/BST多层薄膜结构与性能研究

利用脉冲激光沉积法在LaNiO3/LaAlO3(001)基片上生长了Ba0.6Sr0.4TiO3(BST)和Ba(Zr0.2Ti0.8)O3(BZT)单层薄膜,以及Ba(Zr0.2Ti0.8)O3/Ba0.6Sr0.4TiO3/Ba(Zr0.2Ti0.8)O3(BZT/BST/BZT)多层薄膜.X射线衍射(XRD)分析发现,BST、BZT和LNO薄膜都具有高度的(00l)取向.原子力显微镜(AFM)显示三种样品表面光滑无裂纹,晶粒尺寸和表面粗糙度相当.电容测试表明,相对BST、BZT单层薄膜,多层薄膜具有最大的品质因数42.07.表明多层薄膜在微波应用中具有很大的潜力.     

涂料型La1-xSrxMnO3智能热控涂层的研究

以固相反应法制备了高纯度La0.8Sr0.2MnO3粉体,并以其为基料,磷酸二氢铝为粘结剂,采用涂覆工艺在铝基片上制备了涂料型La0.8Sr0.2MnO3热控涂层.采用XRD、EDS对La0.8Sr0.2MnO3粉体的成分进行了表征,用稳态卡计法测量了涂层在100~100℃温度区间内热辐射率随温度的变化,并测量了涂层的太阳吸收比.研究结果表明:粉体合成过程中,经过1200℃三次热处理制备的La0.8Sr0.2MnO3粉体纯度高,合成的粉体具有均匀的微米级粒径尺寸.通过适当调整浆料中La0.8Sr0.2MnO3粉体所占质量百分比,获得辐射率变化范围大于0.3的热控涂层,该性能与采用烧结工艺制备的La0.8Sr0.2MnO3陶瓷片材料在变温条件下的辐射率变化范围接近.该涂层在航天器热控技术中具有潜在的应用前景.     

草酸盐共沉淀法合成锂离子电池LiNixMn0.8-xCo0.2O2（x=0.4,0.5）正极材料及电化学性能

采用草酸盐共沉淀法,结合高温固相反应法,合成了LiNix Mn0.8-x Co0.2O2(x=0.4,0.5)粉末材料,考察了焙烧时间和镍含量对LiNix Mn0.8-x Co0.2O2(x=0.4,0.5)结构与性能的影响。采用XRD、SEM和电池充放电测试方法等表征了材料的结构与性能。结果表明,800℃焙烧20h制备的LiNi0.5Mn0.3Co0.2O2具有良好的层状结构和综合电化学性能,阳离子混排程度小、六角晶格有序性好。0.2C倍率首次入放电容量为151mAh/g,循环20次后放电容量为148.4mAh/g。SEM结果表明LiNi0.5Mn0.3Co0.2O2是由0.5μm的一次颗粒组成,LiNi0.4Mn0.4Co0.2O2材料由0.5μm的一次颗粒团聚而成约8μm的二次颗粒组成。     

High-K (Ba0.8Bi0.2)(Zn0.1Ti0.9)O3 ceramics for high-temperature capacitor applications

Solid solutions of BaTiO(3)-Bi(Zn(1/2)Ti(1/2))O(3) were investigated for high-temperature capacitor applications. Compositions close to 0.8BaTiO(3)-0.2Bi(Zn(1/2)Ti(1/2))O(3) revealed pseudo-cubic symmetry and showed a linear dielectric response. The existence of a nearly flat temperature dependence of the relative permittivity over the temperature range of 100 to 350°C was also obtained. In this study, the effects of cation non-stoichiometry and doping were investigated in an attempt to optimize the insulation resistance for high-temperature applications. The dielectric response of (Ba(0.8)-xBi(0.2))(Zn(0.1)Ti(0.9)) O(3) ceramics where 0 ≤ X ≤ 0.08, as well as ZrO2- and Mn(2)O(3)-doped ceramics were studied. The optimum compositions exhibited a relative permittivity in excess of 1150 with a low loss tangent (tan δ < 0.05) that persisted up to a temperature of 460δC. The temperature dependence of resistivity also revealed the improved insulation resistance of Ba-deficient compositions. Additionally, we suggest that an ionic conduction mechanism is responsible for the degradation of resistivity at high temperatures. The temperature coefficient of permittivity ((τ)K) and the RC time constant were also investigated.     

阴极材料Ba0.5Sr0.5Co0.8Fe0.2O3-σ合成工艺优化

为了在较低温度下合成具有高纯度的阴极材料Ba0.5Sr0.5Co0.8Fe0.2O3-σ(BSCF),采用X射线、扫描电镜以及能谱分析等方法,研究了共沉淀合成法中溶液pH值和煅烧温度等工艺条件对产物的相结构、组成成分和颗粒形貌的影响.结果表明,pH值的升高使前驱体由草酸盐沉淀向氢氧化物沉淀转化,在pH=10条件下,前驱体1100℃煅烧2 h后形成了单一的立方型钙钛矿型结构,比在pH=6条件下的前驱体煅烧温度降低了约100℃,而且成分配比更为准确.研究认为前躯体溶液的pH值对煅烧产物的组成和形貌影响至关重要,这主要是由于pH值的不同改变了前驱体的组成和颗粒形貌造成的.     

Structure Stability and Oxygen Permeability of Perovskite-type Oxides of Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.1)R_(0.1)O_ (3-δ)(R=Al,Mn,Fe,Ce,Cr,Ni,Co)

Perovskite-type Ba 0.5 Sr 0.5 Co 0.8 Fe 0.1 R 0.1 O 3 δ (R=Al,Mn,Fe,Ce,Cr,Ni,Co) oxide membranes were exploited and synthesized.Oxygen behavior,order-disorder transition and phase stability of these composite oxides were investigated by combined analysis of X-ray diffraction (XRD),temperature programmed desorption (TPD),thermogravimetric-differential thermal analysis (TG-DTA).Oxygen permeation through these membranes was studied by the gas chromatography (GC) method using a high-temperature permeation cell in a wide temperature range from 700 to 950 C.High permeation fluxes were observed for these materials.The high permeation flux was about 3.19 ml·min 1 ·cm 2 under air/He gradients at 950 C,which was achieved for Ba 0.5 Sr 0.5 Co 0.8 Fe 0.1 Ni 0.1 O 3 δ (BSCFNiO) membrane.The results of analysis showed no phase transition for BSCFNiO oxide with increasing temperature and XRD pattern of this material after O 2-TPD indicated to sustain a pure perovskite structure after oxygen permeation process.     

(Pb_(0.5)Sr_(0.5))TiO_3薄膜的表面化学态研究

用溶胶-凝胶法制备(Pb_(0.5)Sr_(0.5))TiO_3(简称PST)前驱体溶液,以三水醋酸铅、醋酸锶、钛酸丁酯为原料,乙二醇甲醚、去离子水、乙酰丙酮做溶剂,通过旋涂工艺在Pt/Ti/SiO_2/Si(100)基片上沉积PST薄膜.薄膜经320～380℃热分解,再经650℃退火30min,得到晶化好的薄膜样品,X射线衍射结果表明PST薄膜为钙钛矿立方相结构,其晶格常数为a=0.3919nm.用原子力显微镜观测其表面形貌,薄膜平均晶粒尺寸为300nm.用XPS测量了650℃退火PST薄膜样品的表面化学态,结果表明表面富铅,接近表面区域的原子比率Pb∶Sr∶Ti∶O是0.52∶0.50∶1.0∶3.02,接近(Pb_(0.5)Sr_(0.5))TiO_3的理想配比.     

水基金属有机物分解法制备Ba0.5Sr0.5TiO3薄膜的研究

制备了水基Ｂａ＾２＋、Ｓｒ＾２＋、Ｔｉ＾４＋三元有机物溶液。根据红外光 谱测定及对比实验分析了溶液配制过程中化学反应机理。采用金属有机物分解法（ＭＯＤ）制备Ｂａ０．５Ｓｒ０．５ＴｉＯ３（ＢＳＴ）薄膜。通过ＸＲＤ、ＳＥ趱 阻抗分析仪等分析测试手段,薄膜的相结构、微观形态及电性能。结果表明,所制备ＢＳＴ薄 数矿晶相结构,结晶完整晶粒小（１０－５０ｎｍ）,显微结构均匀致密,并具有良好的电性能（电容密度为     

Cobalt-free Composite Ba_(0.5)Sr_(0.5)Fe_(0.9)Ni_(0.1)O_(3-δ)-Ce_(0.8)Sm_(0.2)O_(2-δ) as Cathode for Intermediate-Temperature Solid Oxide Fuel Cell

New cobalt-free composites consisting of Ba0.5Sr0.5Fe0.9Ni0.1O3-δ(BSFN) and Ce0.8Sm0.2O2-δ(SDC) were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell (IT-SOFC). BSFN, which was synthesized by auto ignition process, was chemically compatible with SDC up to 1100℃ as indicated by X-ray diffraction analysis. The electrical conductivity of BSFN reached the maximum value of 57 S·cm-1 at 450℃. The thermal expansion coefficient (TEC) value of BSFN was 30.9×10-6K-1 , much higher than that of typical electrolytes. The electrochemical behavior of the composites was analyzed via electrochemical impedance spectroscopy with symmetrical cells BSFN-SDC/SDC/BSFN-SDC. The area specific interfacial polarization resistance (ASR) decreased with increasing SDC content of the composite. The area specific interfacial polarization resistance (ASR) at 700℃ is only 0.49, 0.34 and 0.31 Ω·cm2 when 30, 40, and 50 wt% SDC was cooperated to BSFN, respectively. These results suggest that BSFN-SDC is a possible candidate for IT-SOFC cathode.     

Thermomechanical Analysis of (Cu0.5Tl0.5)-1223 Substituted by Pr and La

The thermomechanical analysis (TMA) of Cu 0.5 Tl 0.5 Ba 2 Ca 2 x R x Cu 3 O 10 δ,where R=Pr and La,with 0.0≤x≤0.15,was carried out in temperature range from 450 to 1145 K.The samples were prepared by singlestep solid state reaction technique.The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The superconductivity of the prepared samples was investigated by electrical resistivity measurement.The results showed that low substitution content enhanced the (Cu 0.5 Tl 0.5)1223 phase formation,while the higher substitution content degraded this phase.The higher superconducting transition temperatures T c were found to be 114 K and 109 K at x= 0.025 for Pr-and La-substitutions,respectively.The average linear thermal expansion coefficient increased as x increased,while the shrinkage temperature decreased as x increased.Those results were emphasized by porosity and Vickers microhardness calculations.Debye temperature θ D was calculated from the linear thermal expansion coefficient data and correlated to T c to estimate the electron-phonon coupling λ ep.