溶胶凝胶法制备WO_3-MoO_3复合薄膜的气致变色性能(英文)

采用溶胶凝胶技术分别制备了 WO3 和 MoO3溶胶,PdCl2作为催化剂被掺入 WO3-MoO3复合溶胶中,然后采用提拉浸渍镀膜法成功制备了 WO3-MoO3复合薄膜。采用原子力显微镜和 X 射线衍射仪分别研究了薄膜的表面形貌和薄膜的晶态结构。采用紫外可见分光光度计原位测试了 WO3-MoO3复合薄膜的气致变色性能。研究表明,该法制备的非晶体的 WO3-MoO3复合薄膜也具有很好的气致变色性能。     

Cu/Al2O3(Cr2O3)复合材料的耐磨损性能

研究了不同工艺制备的Cu/Al2O3(Cr2O3)复合材料的耐磨损性能,结果表明:Cu/Al2O3(Cr2O3)复合材料的磨损机制以磨粒磨损为主.Cu/Al2O3复合材料的耐磨损性能要优于同样条件下制备的Cu/Cr2O3复合材料.当Al或Cr与Cu形成预合金后而进行原位氧化合成的Cu/Al2O3(Cr2O3)复合材料的耐磨性优于当未形成预合金粉末原位氧化合成的Cu/Al2O3(Cr2O3)复合材料的耐磨性.     

MoSi_2-Mo_5Si_3复合材料的低温氧化行为

通过热重分析 (TGA)、X射线衍射 (XRD)和扫描电镜 (SEM)研究了 Mo Si2 - Mo5Si3复合材料的低温氧化行为 ,指出材料低温氧化时 ,随 Mo5Si3量增多 ,材料氧化加剧 ,当 Mo5Si3含量超过 16 % (质量分数 )时发生“PEST”现象 ,所形成的 Si O2 由于 Mo O3晶须的大量存在 ,使其不能均匀连续地分布于材料表面 ,从而加剧了氧化     

MoSi2—Mo5Si3复合材料的低温氧化行为

通过热重分析（TGA）、X射线衍射（XRD）和扫描电镜（SEM）研究了MoSi2-Mo5Si3复合材料的低温氧化行为,指出材料低温氧化时,随Mo5Si3量增多,材料氧化加剧,当Mo5Si3含量超过16％（质量分数）时发生“PEST”现象,所形成的SiO2由于MoS3晶须的大量存在,使其不能均匀连续地分布于材料表面,从而加剧了氧化。     

AlN/SiC_w(Y_2O_3SiO_2)复合材料热处理增强机理

利用ＸＲＤ， ＥＰＭＡ 和ＨＲＥＭ 等测试技术对ＡｌＮ／ＳｉＣｗ（Ｙ２Ｏ３ＳｉＯ２） 复合材料热处理增强机理进行了研究。结果表明： 材料在１ ３００ ℃空气中进行热处理， 其氧化处理过程也是其热处理增强过程， 增强机理主要是由于氧化扩散改变了粒界玻璃相的相组成， 粒界玻璃相在高温氧化气氛下和ＡｌＮ颗粒发生作用， 生成ＡｌＮ 多形体２ＨδＳｉａｌｏｎ 相， 并与ＳｉＣ 晶须形成空间交错的结构     

预氧化对TiC-TiB2/MoSi2复合材料低温氧化行为的影响

研究了20vol％TiC-TiB2/MoSi2复合材料和高温预氧化处理后材料在500℃的低温氧化行为.结果表明,该复合材料在500℃的氧化动力学基本呈线性关系,氧化240h后增重1.67 mg· cm-2,表面生成的氧化层呈疏松多孔并出现“粉化”现象;1200℃预氧化处理的材料在500℃氧化240h后仅增重0.062 mg· cm-2,没有出现“粉化”现象;预氧化处理后的材料表面形成致密的TiO2和SiO2复合保护膜提高了复合材料的低温抗氧化能力.     

Al2O3/ZrO2(Y2O3)复合材料断裂过程中的相变及力学性能

用真空烧结方法制备了Al2O3/ZrO2(Y2O3)复合材料,分析了ZrO2(3Y)和ZrO2(2Y)含量对Al2O3基陶瓷抗弯强度、断裂韧性的影响.用XRD定量分析了含摩尔分数2%与3%Y2O3的ZrO2(2Y)与ZrO2(BY)在断裂过程中四方相转变成单斜相的相变量,用以阐明增韧机制.结果表明,在ZrO2含量为15%(体积分数)时,Al2O3/ZrO2(3Y)和Al2O3/ZrO2(2Y)复合材料的抗弯强度、断裂韧性分别达到825MPa,7.8MPa·m1/2和738MPa,6.7MPa·m1/2,两者的性能差异主要来自不同的增韧机制.     

LiOH-Li_2CO_3低共熔混合锂盐体系合成LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2

利用低共熔组成的0.24LiCO3-0.76LiOH混合锂盐体系,与钴、镍、锰的球形氢氧化物按1.1:1混合,无需前期球磨,直接经二段控温程序制备出锂离子正极材料LiNi1/3Co1/3Mn1/3O2。X射线衍射分析表明合成的Li(Ni1/3Co1/3Mn1/3)O2结晶度高,具有规整的层状α-NaFeO2结构,扫描电镜显示产物颗粒均匀,振实密度高达2.89g·cm-3,显著高于用单一锂盐制备的同样产品(2.4g·cm-3)。充放电测试表明,材料具有良好的电性能,首次充放电容量为176和166mhA·g-1,循环50次后,材料的电性能没有明显的衰减。     

低温共烧(LTCC)BaO-Nd2O3-TiO2陶瓷研究

研究了BNT(BaO-Nd2o3-Tio2)陶瓷中添加BZB(B2o3.ZnO-Bi2o3)玻璃后对烧结温度以及介电性能的影响.经过测试玻璃一陶瓷混合体的微波介质性能,发现该玻璃能将烧结温度降低到900℃或者更低.这是由于低软化点的BZB玻璃和高熔点的BNT相互作用,使得BNT和BZB之间润湿良好.BNT-BZB在900℃下烧结,具有优良的介电性能,表现为介电常数ε约为75,损耗tanδ约为5%,温度系数TCC约为0.5%,绝缘电阻大于1011Ω.结果表明这种体系可以用来作为高频应用的低温共烧材料.     

铝熔体中添加NH4Al(SO4)2制备Al/Al2O3复合材料

向铝熔体中添加脱水的硫酸铝铵,于900℃下发生分解反应,反应分解的Al2O3原位生成颗粒增强铝基复合材料。SEM观察表明,Al2O3颗粒在铝基体中细小弥散分布,形成球形的、不团聚的增强体颗粒。与基材相比,Al/Al2O3复合材料的耐磨损性能明显提高,耐磨性是基材的4倍,且由硫酸铝铵原位生成的复合材料耐磨性优于添加氧化铝形成的复合材料。拉伸实验结果显示,复合材料的抗拉强度没有明显变化,且塑性有所降低。     

WO3-TiO2复合空心球的制备及其光催化性能

以钛酸四正丁酯和偏钨酸铵为原料,采用水热-模板法制备复合WO3-TiO2光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积(BET)和紫外-可见漫反射(UV-Vis DRS)等手段对催化剂的结构和光学性能进行表征。结果表明:WO3-TiO2复合半导体中的TiO2为锐钛矿晶型,焙烧后的WO3-TiO2呈中空球形结构,粒径在320 nm左右,且粒径分布均匀,其比表面积和平均孔径分别为40.95 m2/g和16.91 nm,WO3-TiO2复合半导体的紫外-可见吸收边带较TiO2的红移约50 nm,并在400~500 nm处有吸收。光降解甲基橙(MO)实验显示:经过80 min光照后,WO3-TiO2复合半导体在紫外和可见光下对甲基橙的降解率分别为99.2%和81%,而TiO2的仅为64%和25%,且在紫外和可见光下WO3-TiO2复合半导体的表观速率常数分别是TiO2的3.2和4.9倍左右。     

Subsolidus phase relations in the ZnO–MoO3–B2O3, ZnO–MoO3–WO3 and ZnO–WO3–B2O3 ternary systems

The subsolidus phase relations in the ZnO–MoO₃–B₂O₃, ZnO–MoO₃–WO₃ and ZnO–WO₃–B₂O₃ ternary systems have been investigated by the means of X-ray powder diffraction (XRD). There is no ternary compound in all the systems. There are five binary compounds and five tie lines in the ZnO–MoO₃–B₂O₃ system. This system can be divided into six 3-phase regions. There are three binary compounds and three tie lines in the ZnO–MoO₃–WO₃ system. This system can be divided into four 3-phase regions. There are four binary compounds and four tie lines in the ZnO–WO₃–B₂O₃ system. This system can be divided into five 3-phase regions. The possible component regions for ZnO single crystal flux growth were discussed. The phase diagram of Zn₃B₂O₆–ZnWO₄ pseudo-binary system has been constructed, and the result reveals this system is eutectic system. The eutectic temperature is 1007 °C and eutectic point component is 70 mol% Zn₃B₂O₆.     

基于纳米NiO颗粒敏感电极的NO2气敏特性研究

利用浸渍技术在YSZ多孔层中制备NiO纳米颗粒材料,并以其为敏感电极组成新型的电流型NO2传感器。采用X射线衍射仪、扫描电子显微镜表征了NO2传感器物相和形貌结构,应用IM6e型电化学工作站测试了其气敏性能。实验结果表明:NiO颗粒粒度约50nm,且分布均匀。在500~600℃时,传感器对NO2有良好的敏感性,其响应电流值与NO2的浓度之间呈良好的线性关系。传感器对NO2响应时间短且响应信号稳定。O2和CO2的存在对传感器响应信号几乎没有影响。     

不同溶胶-凝胶镀膜技术制备的电致变色WO3薄膜的影响

研究了不同溶胶-凝胶镀膜技术对电致变色WO3薄膜的影响.采用过氧化聚钨酸法配制溶胶,然后通过脉冲电泳沉积和浸渍提拉两种镀膜技术在ITO导电玻璃基底上分别制备WO3薄膜,对比研究了薄膜的微观形貌、结构、光学和电化学性能.结果表明,两种镀膜技术制备的薄膜均为非晶态且厚度相近,约为252 nm;在可见光范围内,脉冲电泳沉积制备的薄膜的光学调制幅度可达80％,比浸渍提拉制备的薄膜高25％;与浸渍提拉法相比,脉冲电泳沉积制备的薄膜具有更高的电化学活性、更快的响应时间和相对低的循环可逆性.     

The ternary system Na2O–ZnO–WO3: Compounds and phase relationships

The subsolidus phase relationships of ternary system Na₂O–ZnO–WO₃ have been investigated by X-ray diffraction (XRD) and differential thermal analyzer (DTA). All the samples were synthesized in the temperature range from 530 to 850 °C in air. There are one ternary compound and five binary compounds in the Na₂O–ZnO–WO₃ system, which can be divided into eight three-phase regions. The crystal structure of the ternary compound Na_3.6Zn_1.2(WO₄)₃ is determined by single-crystal structure analysis method. It belongs to triclinic system with space group and lattice constants a = 7.237 (5) Å, b = 9.172 (6) Å, c = 9.339 (6) Å and  = 94.920 (4)°, β = 105.772 (9)°, γ = 103.531 (8)°, Z = 2. DTA analyses indicate that the compound Na₂WO₄ is not suitable to be the flux for ZnO crystal growth below 1250 °C, since no liquidus was observed in the system before 1250 °C.     

硝酸铈添加剂对7075铝合金微弧氧化陶瓷膜

为进一步提高7075铝合金的表面耐磨性,在硅酸钠、六偏磷酸钠复合电解液中加入不同质量浓度的硝酸铈添加剂,运用微弧氧化技术在其表面原位生长出氧化铝陶瓷膜。采用涂层测厚仪、维氏硬度计、扫描电子显微镜(SEM)、X射线衍射议(XRD)等方法研究了硝酸铈添加剂对陶瓷膜厚度、显微硬度、表面形貌、相组成以及耐磨性的影响。结果表明： 陶瓷膜主要由αAl2O3和γ Al2O3两相组成,当硝酸铈质量浓度为0.12 g/L,陶瓷膜的厚度达到最大,约为18 μm;硬度达到最高,约为916 HV0.2;致密性最佳;陶瓷膜表现出更好的耐磨性能。     

Surface modification of spherical LiNi1/3Co 1/3 Mn1/3O2 with Al2O3 using heterogeneous nucleation process

To improve the cycle stability at high voltage and high charge/discharge rate, spherical LiNi1/3Co1/3Mn1/3O2 was coated with Al2O3 by using heterogeneous nucleation process, and the physical and electrochemical properties were studied. The SEM images show that there is a uniform coating on the modified spherical LiNi1/3Co1/3Mn1/3O2. The electrochemical tests indicate that the properties of LiNi1/3Co1/3Mn1/3O2 coated with 0.5% aluminum oxide are the best. The initial capacities are 150 and 173 mA.h/g at the rate of I C in the voltage range of 2.7-4.3 V and 2.7-4.6 V, respectively, and the discharge capacities maintain about 99% and 85% after 30 cycles, respectively. While those of the bare LiNi1/3Co1/3Mn1/3O2 are only 90% and 75%, respectively. The CV tests of LiNi1/3Co1/3Mn1/3O2 show that Al203-coating can restrain the oxide-reduction peak currents fading during the charge/discharge course.     

Enhanced NO2 sensing characteristics of Pd-functionalized networked In2O3 nanowires

In this work, we fabricated Pd-functionalized networked In₂O₃ nanowires. For the Pd-functionalization, In₂O₃-Pd core-shell nanowires were synthesized by depositing Pd layers using a sputtering method on bare In₂O₃ nanowires. The continuous Pd shell layers were transformed into islands of cubic Pd/PdO phase by thermal heating. We compared the NO₂ sensing characteristics of the sensors fabricated from Pd-functionalized and bare In₂O₃ nanowires, respectively. The results demonstrated that Pd functionalization greatly improves sensitivity and response time in In₂O₃ nanowire-based gas sensors. The improvement of sensing properties is likely caused by not only the enhanced adsorption or dissociation of NO₂, but also the associated spillover effects, which are both caused by the Pd-functionalization.     

Crystal structures and structural relationships of KFe2(SeO2OH)(SeO3)3 and SrCo2(SeO2OH)2(SeO3)2

The new phases KFe₂(SeO₂OH)(SeO₃)₃ and SrCo₂(SeO₂OH)₂(SeO₃)₂ have been synthesized under low-hydrothermal conditions and their structures were determined by single-crystal X-ray methods. Both compounds are monoclinic; KFe₂(SeO₂OH)(SeO₃)₃: space group P2, A = 9.983(4), B = 5.270(1), C = 10.614(4) Å, β = 97.42(2)°, V = 553.7 ų, Z = 2; SrCo₂(SeO₂OH)₂(SeO₃)₂: space group P2ln, A = 14.984(2), B = 5.286(1), C = 13.790(2) Å, β = 94.72(1)°, V = 1088.5 ų , Z = 4. The refinements converged to R-values of 2.9 and 3.6% respectively.

The atomic arrangement in KFe₂(SeO₂OH)(SeO₃)₃ and SrCo₂(SeO₂OH)₂(SeO₃)₂ is based on isolated MO₆ octahedra (M = Fe³⁺, Co²⁺), which are corner-linked via trigonal pyramidal selenite groups to a framework structure. Interstitials are occupied by potassium or strontium atoms in ten- or eight-coordination respectively, and by the lone-pair electrons of the Se⁴⁺ atoms. Both compounds are not isotypic but are closely related and may be interpreted as different distortions of an idealized structure type in space group P2/m, which was modelled for a theoretical compound SrFe₂(SeO₃)₄ by distance least squares refinement (program ).