固体氧化物燃料电池电解质8YSZ薄膜的水系流延

本文采用水系浆料流延成型法制备固体氧化物燃料电池SOFC的电解质材料(8;摩尔分数Y2O3,稳定的ZrO2,下称8YSZ)薄膜,研究了三种不同类型的分散剂对8YSZ浆料稳定性的影响.通过优化pH值和分散剂用量等因素,使浆料的稳定性达到最佳,获得固相含量高达62;质量分数的适合流延的8YSZ水系浆料.以该浆料为原料,采用流延的方法成型8YSZ薄膜,获得了显微结构均匀、相对密度达49.4;、表面光滑、无裂纹、柔韧性好、干燥后厚度为50 μm左右的薄膜素坯.该素坯在1350℃保温4 h烧结得到相对密度大于96;的致密8YSZ烧结薄膜.     

分散剂对CSLST微波介质陶瓷水系流延浆料稳定性的影响

分别采用聚乙烯吡咯烷酮(PVP)、聚乙烯酸(PAA)、聚丙烯酰胺为分散剂,以苯丙乳液为粘结剂,丙三醇为增塑剂,去离子水为分散介质,水系流延成型法制备添加B2O3-CuO-LiCO3(BCL)玻璃料为烧结助剂的(Ca0.9375Sr0.0625)03(Li0.5Sm0.5)07TiO3 (CSLST)微波介质陶瓷,研究了分散剂种类及含量对陶瓷粉体浆料分散稳定性以及流延膜片的影响.结果表明:当以PVP为分散剂,添加量为0.8;,调节浆料的pH=10时,浆料的分散稳定性最佳,经流延后可制备得到表面光滑,均匀无裂纹的延膜片.     

CSLST微波介质陶瓷的流延浆料的制备工艺研究

以二甲苯,正丁醇混合溶液作为分散溶剂,自制的BM-2为粘结剂,聚乙二醇PEG为增塑剂对添加烧结助剂B2O3-CuO-LiCO3 (BCL)的(Ca0.9375Sr0.0625)0.2(Li0.5Sm0.5)0.8TiO3 (CSLST)微波介质陶瓷粉体进行流延浆料制备工艺研究.通过研究各种添加剂含量对含55;陶瓷基料粉体的浆料流变性能的影响,得出了合适的浆料添加剂配比为:混合溶液二甲苯与正丁醇的比例为1∶1(体积比),粘结剂BM-2为8wt;～11wt;,增塑剂PEG为2wt;～3wt;.该浆料具有典型剪切变稀行为的塑性流体特性,经流延可制备均匀无裂纹的流延膜片.膜片叠层后在875℃下烧结具有较佳的微波介电性能:介电常数εr=51.8,品质因数Q×f=1085 GHz,谐振频率温度系数τf=19.38×10-6/℃.     

水基流延制备Li1.075Nb0.625Ti0.45O3微波介质陶瓷基片

以聚乙烯醇水溶液为粘结剂,乙二醇为增塑剂,聚羧酸铵盐为分散剂,通过水基流延工艺制备了Li1.075Nb0.625Ti0.45O3(LNT)微波介质陶瓷基片.对Li1.075Nb0.625 Ti0.45O3微波介质陶瓷水基流延浆料流变特性的研究表明,当分散剂用量为0.6 wt;.粘结剂用量为5 wt;,增塑剂用量为10 wt;时,流延浆料分散稳定性良好,呈现典型的剪切变稀型流体特性,满足流延成型工艺的要求.采用该配方制备的Li1.075Nb0.625Ti0.45O3水基流延基片力学性能良好,基片的微观结构均匀.     

ZrO2陶瓷流延浆料的流变特性的研究

本文探索了纳米ZrO2粉的流延浆料的流变特性.以体积比为1:1的丙酮和无水乙醇为混合溶剂,粘结剂选用聚乙烯缩丁醛(PVB),分散剂选用甘油三酯(TG),邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二辛酯(DOP)为增塑剂配置了ZrO2陶瓷浆料.研究了浆料的固相体积以及各种有机添加剂的添加量对其流变性能的影响.结果表明:固相含量为60wt;,分散剂量为1wt;,粘结剂添加量为5wt;,增塑剂与粘结剂的质量比为1～1.3,浆料流变性能良好,浆料粘度达到了2200 mPa·s左右;制备出良好无缺陷ZrO2陶瓷基片.     

纳米Y2O3悬浮液流变性能及注浆成型研究

以比表面积为18.1 m2/g的纳米粉体Y2O3为原料,柠檬酸铵(TAC)作为分散剂制备Y2O3悬浮液,研究TAC含量、pH值、球磨时间及固相含量对Y2 O3悬浮液流变性能的影响.结果表明:加入2.2;(质量分数)的TAC,调节悬浮液的pH值为9.4～11.5,球磨8 h可以获得分散稳定的Y2 O3悬浮液;悬浮液的粘度随固相含量的增加而增大,对不同固相含量的悬浮液进行注浆成型,发现固相含量为33;(体积分数)的悬浮液致密度最高.与传统的模压成型工艺相比,注浆成型得到的坯体中粉体颗粒分散均一.     

ZnO/TiO2复合光阳极染料敏化太阳能电池的研究

采用醇热法制备ZnO纳米粉体,采用水热法制备TiO2纳米粉体,将不同质量分数的ZnO与TiO2混合制备浆料,采用刮涂法在掺氟的SnO2透明导电玻璃(FTO)上制备ZnO/TiO2纳米复合薄膜光阳极,与Pt对电极和电解质组装成染料敏化太阳能电池.采用X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)和扫描电镜(SEM)对所制备的样品进行表征,通过光电性能测试和电化学阻抗谱测试,研究了添加不同质量分数的ZnO对电池性能的影响.结果表明:不添加ZnO纳米粉时,纯TiO2光阳极的电池光电转换效率为7.95;,而添加了2wt; ZnO的ZnO/TiO2复合光阳极电池的效率达到9.54;,比纯TiO2电池的效率提高了20;.     

钛精矿湿化学法合成Fe2TiO5/TiO2复合纳米粉体

以攀枝花钛精矿作为初始原料,采用湿化学法制备铁钛氧化物纳米粉体.利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM/EDS)、BET氮气吸附法、紫外-可见漫反射光谱(UV-Vis DRS)对合成的粉体进行表征,测试结果表明:合成了相组成为85.72 ;质量分数 Fe2TiO5和14.28 ;质量分数 TiO2(金红石)复合纳米晶粉体,平均晶粒尺寸为38 nm;近似球形的粉体颗粒及其聚集体,比表面积为16.80 m2/g;粉体在波长250～600 nm范围内均有较强的光吸收,由Fe2TiO5电子跃迁形成的起始吸收边为593 nm,相应的能带宽度为2.09 eV.     

纳米BaTiO_3粉体的水系流延研究

以纳米BaTiO3粉体为原料,通过研究BaTiO3的颗粒特性、pH值、分散剂、粘结剂、塑化剂的用量等因素对浆料和流延生坯片性能的影响,成功制备了BaTiO3陶瓷基片。当pH值大于10时,可以有效抑制Ba2+的溶出;分散剂PAA的用量为1.0 wt%时,纳米BaTiO3在水体系中有最佳的分散效果;复合粘结剂的用量为5 wt%~8 wt%(D-1070∶PVA=7∶3),塑化剂与粘结剂质量比为4∶5时,可获得综合性能较好的生坯片。所得的流延生坯片相对密度达55%,BaTiO3颗粒在坯片中分散均匀。在1300℃烧结,可以得到平整、无缺陷、相对密度达98.5%的BaTiO3陶瓷基片。     

水系流延技术制备95氧化铝陶瓷基片的研究

本论文采用水系流延技术制备了95氧化铝陶瓷基片,主要对浆料中各种添加剂的作用作了系统研究.分散剂通过与无机粉料的吸附,提供双重稳定效应使浆料具有较好的分散性,实验中分散剂PAA(聚丙烯酸)最佳的用量为0.5wt;.粘结剂PVA(聚乙烯醇)最佳用量为4.5wt;.塑化剂PEG(聚乙二醇)的加入可以降低粘结剂的玻化温度,提高坯片柔韧性.塑化剂与粘结剂的用量比值(R)在1～1.2之间为宜.最终获得了具有一定强度、韧性、表面光滑的坯片,烧结出密度为3.785g/cm395氧化铝陶瓷基片.     

(C2N2H10)2Mg(HP2O7)2·2H2O synthesis and crystal structure

(C₂N₂H₁₀)₂Mg(HP₂O₇)₂·2H₂O, is a new inorganic organic hybrid structure. It has been synthetized using wet chemistry. Its crystal structure consists of cis- and trans-edge sharing [MgO₄(H₂O)₂] octahedra resulting in chains, which are linked via [HP₂O₇] units to form [Mg(HP₂O₇)₂(H₂O)₂]⁴⁻ layers. The Mg²⁺ cations and the ethylendiammonium cations are located on centers of inversion. The ethylendiammonium cations are alternately located in the interlayer space. The cohesion of the crystal is well ensured by coulombic interactions between anions and cations and by several hydrogen bonds. The diphosphate anion shows an eclipsed conformation.     

Crystal structure of Rb2[GeO2(OH)2]·2H2O

Single crystals of Rb₂[GeO₂(OH)₂] · 2H₂O are studied by X-ray diffraction. The crystals belong to the orthorhombic system, sp. gr. Pna2₁, a = 13.523(6) Å, b = 8.143(4) Å, c = 13.407(6) Å, Z = 8, R ₁ = 0.0506. In [GeO₂(OH)₂]^2? anions, the Ge-O distances (1.71–1.73(1) Å) are shorter than the Ge-OH distances (1.76–1.80(1) Å). Anions are linked to each other by pairs of hydrogen bonds to form infinite chains. The chains are linked by hydrogen bonds involving water molecules to form a 3D structure. The assignment of the bands in the IR spectrum of the compound under study is performed.     

Ultraviolet Absorption of Hg2Cl2-and Hg2Br2 Single Crystals

The optical unpolarized absorption spectra of Hg₂Cl₂ and Hg₂Br₂ single crystals were measured in the spectral range 230–400 nm. A sharp exciton peak and other absorption bands of both halides were observed near the fundamental absorption edge. The absorption peaks due to the splitting of the halogen doublet were also observed. Positions of the exciton peaks are characteristic for the Frenkel (localized) type of excitons. Possible interpretations of the other observed bands are discussed.     

Optical properties of the germanate melilites Sr2MgGe2O7, Sr2ZnGe2O7 and Ba2ZnGe2O7

Refractive indices and their dispersion in the wavelength range from 365 nm to 2325 nm and transmission ranges of the tetragonal melilite‐type germanates Sr₂MgGe₂O₇, Sr₂ZnGe₂O₇ and Ba₂ZnGe₂O₇ were determined. The uniaxial positive crystals Sr₂MgGe₂O₇ and Ba₂ZnGe₂O₇ both offer the possibility for phase matched second harmonic generation, a detailed analysis of phase matching conditions is given. The refractive indices of Sr₂ZnGe₂O₇ show an isoindex (isotropic) point at 467 nm. The investigation was performed on Czochralski grown large single crystals. The crystal structure of all three germanates were determined by means of X ‐ray diffraction. The results corroborate unmodulated melilite‐type structures at room temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Identification of a new family of diphosphate compounds, AI2BII3(P2O7)2: Structures of Ag2Co3(P2O7)2, Ag2Mn3(P2O7)2, and Na2Cd3(P2O7)2

Syntheses and single-crystal X-ray structural results are reported for three new mixed diphosphates of the family A^I ₂B^II ₃(P₂O₇)₂; Ag₂Co₃(P₂O₇)₂ (I), Ag₂Mn₃(P₂O₇)₂ (II), and Na₂Cd₃(P₂O₇)₂ (III). All crystallize in the triclinic system, space group P1 bar: (I) a = 5.351(4), b = 6.375(4), c = 16.532(4) Å, = 80.83(6) = 81.45(4), = 72.87(5)°, V = 528.9(6) ų, Z = 2, D _calc = 4.649 mg/m³, R/Rw = 0.0428/0.0548 for 3949 obs. reflns; (II) a = 5.432(7), b = 6.619(6), c = 16.51(3) Å, = 80.78(8) = 82.43(9), = 72.82(7)°, V = 557.7(13) ų, Z = 2, D _calc = 4.338 mg/m³, R/Rw = 0.0679/0.1303 for 2100 obs. reflns and (III) a = 5.67(3), b = 7.08(4), c = 7.90(4) Å, = 77.0(2), = 82.5(2), = 67.8(2)°, V = 286(3) ų, Z = 2, D _calc = 4.249 mg/m³, R/Rw = 0.0307/0.0342 for 1945 obs. reflns. (I) and (II) are isostructural but (III) is of a different type. All three structures are characterized by layers of P₂O₇ groups alternating with layers of mixed metal atoms. Differences are seen in the conglomerate bonding patterns of B atoms and in the irregular geometry of Ag in (I) and (II) compared to the octahedral bonding seen for Na in (III). The differences in structure may be understood in terms of the ratios of the ionic radii of A and B atoms.     

Crystal structure of bis 4-benzyl piperidinium monohydrogenmonophosphate pentahydrate, [C6H5CH2CHCH2CH2NH2CH2CH2]2HPO4·5H2O

The salt bis 4-benzyl piperidinium monohydrogenmonophosphate pentahydrate is orthorhombic with the following unit cell dimensions: a = 11.235(2) Å, b = 27.924(6) Å, c = 9.321(4) Å space group Pca2₁ with Z = 4. The structure was solved by the Patterson method and refined to final R value of 0.049 for 1802 independent reflections. The flack parameter is 0.14 with an e.s.d. of 0.23. The structure consists of infinite parallel two-dimensional [110] planes built of mutually connected ions and water molecules by strong O—H,...,O and N—H,...,O hydrogen bonding. There are no contacts other than normal van der Waals interactions between the layers.     

Synthesis and characterization of (NH4)2CuBr2Cl2·2H2O crystals

Single crystals of a new compound, (NH₄)₂CuBr₂Cl₂.2H₂O, were grown from saturated aqueous solution at room temperature by slow evaporation method. The grown crystals were characterized through elemental, powder XRD, thermal and DSC analyses and FTIR and far IR spectra. The elemental analysis and the decomposition pattern formulated using the TG‐DTG studies confirm the stoichiometry of the compound. The crystallinity of the compound is confirmed from the powder XRD pattern. A preliminary single crystal X‐ray diffraction structural analysis reveals that the title compound belongs to the orthorhombic system with a = 7.7466 Å, b = 7.783 Å and c = 8.1211 Å. The low temperature DSC shows thermal anomalies at –161.1, –156.5, –152.4, –145.2, –134, –18.5, and 1.4°C during the heating run and at –4.3, –54.8, –66.1, –90.6, –109.7 and –147.2 °C during the cooling run. The thermal hysterses indicate first order phase transitions in the title compound at these temperatures. The FTIR spectra were used to assign the characteristic vibrational frequencies due to NH₄⁺, CuX₄^2– ions and other chemical bonds. The effect of substitution of two bromine atoms on the phase transitions of a closely related crystal, diammonium tetrachloro cuprate dihydrate is also discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structure of {Pb[S2CN(C2H5)2]2(1,10-phenanthroline)}2

Lead (II) nitrate reacts with 1,10-phenanthroline and sodium diethyldithiocarbamate in water to produce yellow bisdiethyldithiocarbamata 1,10-phenanthroline lead(II). Crystals from water are triclinic, space group $P\bar 1$ (#2),a=10.53(2) Å,b=11.050(12)Å,c=24.74 (3) Å, α=94.71 (9)⁰, β=98.15(11)^o, γ=114.11(9)^o,V=2569(6) ų,Z=2. Each lead atom has approximate pentagonal pyramid coordination geometry through the nitrogens of a phenathroline and sulfurs of two dithiocarbamates. Additionally, complexes form loose dimers in which lead atoms are weakly coordinated to a sulfur in an adjacent complex. IR and proton nmr spectrum of the complex are consistent with the solid state structure.     

KBe2BO3F2和RbBe2BO3F2晶体中的孪晶缺陷

通过化学腐蚀和偏光显微镜,对KBe2BO3F2(KBBF)和RbBe2BO3F2 (RBBF)晶体中存在的一种条状孪晶缺陷进行了研究,观察了孪晶习性,探讨了其孪晶律,并结合晶体生长情况对该孪晶的形成原因进行了分析.     

Elastic properties of the dithionates Na2S2O6 · 2 H2O,K2S2O6, Rb2S2O6, CaS2O6 · 4H2O and SrS2O6 · 4 H2O

Single crystals of the title compounds having optical quality and dimensions of several cm were grown from aqueous solutions. The elastic and thermoelastic constants were determined from ultrasonic resonance frequencies of thick plates. The true point symmetry of K₂S₂O₆ and Rb₂S₂O₆, which is screened by a hexagonal hypermorphy, could be clearly revealed to be trigonal (32) by the existence of the elastic constant c₁₄. In the case of CaS₂O₆ · 4H₂O and SrS₂O₆ · 4H₂O the constant c₁₄ of the specimens appeared too small to confirm the trigonal symmetry group required from electrooptic and non-linear optic effects unambiguously. The isotypy of K₂S₂O₂ and Rb₂S₂O₆ as well as that of CaS₂O₆ · 4H₂O and SrS₂O₆ · 4H₂O is confirmed by their elastic behaviour. The mean elastic stiffness of dithionates is closely related to that of the corresponding sulphates. In the vicinity of the second-order phase transition of K₂S₂O₆ near 235 K weak anomalies of the temperature derivatives of the longitudinal elastic stiffnesses are observed.