添加Na2WO4对镁合金微弧氧化陶瓷层成分及结构的影响

讨论了添加Na2WO4的Na2SiO3电解液对镁合金微弧氧化陶瓷层成分及结构的影响.结果表明,添加Na2WO4后,陶瓷膜层厚度增加,膜层的致密性和硬度提高,而对膜层的相组成几乎没有影响,说明加入Na2WO4使陶瓷膜层的性能得到改善.     

基于聚噻吩/WO_3的有机-无机复合材料低温NO_2传感器(英文)

通过化学氧化聚合法和胶溶法分别制备了聚噻吩(PTP)和纳米WO3,通过简单机械共混和PTP和WO3制备不同PTP质量分数的有机-无机PTP/WO3复合物。所制备的PTP/WO3复合物比纯的PTP具有更高的热稳定性。气敏测试结果表明,在低温检测NO2时,PTP/WO3复合物具有比纯的PTP和WO3更高的响应,这可能与PTP/WO3复合物中p-n异质节的存在有关系。PTP/WO3复合物的响应受PTP质量分数的影响显著,20%PTP/WO3复合物在低温(90°C)时对NO2显示出高的响应和好的选择性。因此,PTP/WO3传感器有望被用于低温检测NO2     

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。     

WO3纳米片的制备、表征及气敏性能研究

论文采用水热法合成WO₃纳米片,利用扫描电镜(SEM)和X射线衍射(XRD)对WO₃纳米片的形貌特征和结构性能进行表征,并进一步系统地考察了利用WO₃纳米片制备的传感器的气敏性能。实验结果表明,合成的WO₃纳米片尺寸规则,边长在200-300 nm,厚度在50 nm左右,结晶性好。以WO₃纳米片为材料制备的气体传感器的最佳工作温度为300 _oC,在此工作温度下,WO₃纳米片传感器对乙醇表现出超快的响应(2-4秒)和恢复时间(4-16 S)。与其他还原性气体如甲醇,苯、二氯甲烷和正己烷对比检测发现,WO₃纳米片传感器对乙醇表现出高的灵敏度和选择性,表明WO₃纳米片在乙醇检测气体传感器方面具有极大的应用潜力。     

封闭循环氢还原法制备纳米钨粉

通过对WO3氢还原过程的热力学分析,找到了制备均匀细颗粒W粉的热力学途径-彻底快速除去还原系统中的水分。通过系统内的特殊装置除水,降低了还原温度,以WO3为原料,用封闭循环氢还原法,在600℃下还原得到了W粉,其粒径在(20～60)nm之间熏纯度为99.76%。     

基于光固化的全固态电致变色器件制备与性能

目的使用聚乙二醇400(Polyethylene Glycol 400,PEG400)掺杂直接将光固化树脂溶于电解液,并通过光固化先液后固制备全固态电解质。方法使用溶胶-凝胶法制备掺杂了聚乙二醇400的WO_3薄膜,用高氯酸锂粉末、聚碳酸酯(Polycarbonate,PC)、聚甲基丙烯酸甲酯(Polymethyl Methacrylate,PMMA)粉末和光固化树脂(UV-cured resin)配制了凝胶态的电解液。采用毛细封装法对制得的WO_3薄膜进行光固化封装。对制得的电致变色器件进行循环响应时间、光透过率和记忆效应测试,使用扫描电子显微镜对薄膜表面形貌进行分析。结果掺杂了聚乙二醇400的WO_3薄膜表面裂痕明显减少,平均粗糙度为3nm,疏松孔隙结构较多,制得的电致变色器件完全着色时只需要0.5s,而未掺杂PEG400制得的电致变色器件完全着色需要4 s,掺杂了PEG400制得的器件完褪色需要0.5 s,而未掺杂的器件需要1.5 s,且掺杂组比未掺杂组的光调制幅度要高出20%,记忆效应也要更好。结论掺杂PEG400可以使WO_3薄膜表面更加均匀,有效地提升了光调制幅度和降低了循环响应时间,记忆效应也有明显的提升。同时,利用光固化技术制备全固态电致变色器件,制备工艺简单,且易于保存。     

Crystal Structures of Dy_2(WO_4)_3 and GdY(WO_4)_3

Two compounds, Dy2(WO4)3 and GdY(WO4)3, were synthesized by using the standard solid state reaction technique. The crystal structure was determined by powder X-ray diffraction and Rietveld refinement method. It is found that both compounds have Eu2(WO4)3-type monoclinic structure, with space group C 2/c, Z = 4. The unit cell parameters of Dy2(WO4)3 are a = 0.75981(1) nm. b = 1.13220( 1) nm, c = 1.13254( 1) nm, and β= 109.8001(3)°, and those of GdY(WO4)3 are a = 0.76175(1) nm, b = 1.13543(1) nm, c = 1.13496(2) nm, and bbbbbbbbbβwhile each rare-earth atom is surrounded by eight oxygen atoms. WO4 tetrahedra share their four vertices with REO8 (RE = Dy, Gd, or Y) trigondodecahedra and some REO8 trigondodecahedra share an edge with each other. The phase transition and the magnetic properties were investigated by differential thermal analysis (DTA) and dc superconducting quantum interference device (SQUID) magnetometer.     

选择性沉淀法从钨酸盐溶液中除钼的工业试验

对“选择性沉淀法从钨酸盐溶液中除钼”新工艺进行了工业试验。结果表明对处理含WO3130～244g/L,含钼0.535～2.55g/L的工业钨酸铵溶液,除钼后净液中Mo/WO3达到2.00×10     

微量Si在W－7Ni－3Fe高比重合金中的行为

用掺杂微量Ｓｉ的钨粉为原料，制备Ｗ－７Ｎｉ－３Ｆｅ高比重合金，用扫描电镜、Ｘ射线光电子能谱仪等研究了微量Ｓｉ在合金中的行为。结果表明，原料钨粉中的微量ＳｉＯ２在合金中以微粒形式弥散分布在合金的粘结相中，部分Ｓｉ以固溶体形式分布在钨晶粒中；在未掺杂的合金中，发现有少量的ＷＯ２以薄膜形式分布在钨晶粒的表面，而在掺杂了微量Ｓｉ的合金试样中，ＷＯ２薄膜消失。探讨了掺杂微量Ｓｉ消除钨晶粒表面ＷＯ２薄膜的机理。     

ITO/PET衬底上掠射角溅射沉积WO3薄膜及其电致变色性能

采用直流磁控反应溅射法,以不同掠射角度在ITO/PET衬底上沉积WO3薄膜。利用场发射扫描电子显微镜（FE-SEM）和能谱仪（EDS）对WO3薄膜表面和断面的形貌及化学组成进行表征;利用电化学工作站和紫外分光光度计对WO3薄膜的电化学性能和光学性能进行分析。结果表明,当掠射角60时,薄膜表面形成类似于山峰状形貌,断面为纳米斜柱状结构,该结构有利于离子和电子的迁移。当掠射角=80时,沉积的WO3薄膜具有最快离子扩散速率和最大光调制幅度,着色效率达到27.05cm2/C。同时,薄膜还表现出快速响应和良好循环稳定性。     

添加剂对新型AgTiB2触头材料微结构和性能的影响

以乙二胺为溶剂采用微波溶剂热法合成铜铟镓硒(CIGS)粉体,研究了反应温度、表面活性剂对合成产物物相及形貌的影响.采用X射线衍射仪、扫描电镜及X射线能谱仪对产物的物相、形貌及组成进行表征.结果表明:在反应温度为230℃(反应时间为2 h)条件下可以获得物相单一,颗粒尺寸较小的CIGS粉体.在基准溶液中加入表面活性剂十二烷基硫酸钠(SDS)后对合成产物形貌有明显改善作用,粉体分散性较好,呈圆球状且粒径较小,为100～200 nm.     

WO3对TiO2粉体晶型转变的影响

以TiO2为原料,通过引入WO3添加剂,经不同温度煅烧后得到钨掺杂的TiO2粉体.利用XRD和SEM等测试手段,研究煅烧温度、WO3引入量对TiO2粉体晶型转变的影响,并对其机制进行探讨.结果表明:WO3促进了TiO2从锐钛矿向金红石的转变,降低了TiO2的晶型转变温度,随着WO3引入量的增加,促进作用增强.引入的WO3以两种形式促进TiO2的晶型转变:一种是Wn+进入TiO2晶格置换Ti4+而促进了晶型转变;另一种是WO3和TiO2发生氧化还原反应,促进了TiO2的晶型转变.     

采用溶胶-凝胶法在多孔氧化铝模板上制备立方相WO3纳米线

采用溶胶-凝胶法在纳米孔氧化铝模板上成功制备形貌各异的WO3纳米线.X射线衍射分析表明所制备的WO3纳米线为立方相结构.经扫描电子显微镜观察发现产物多数为菊花状WO3纳米线,其直径约10～80 nm,长约几微米.与空气气氛相比,氩气气氛更有助于WCl6三嵌段共聚物溶胶在多孔氧化铝模板上形成形貌各异的WO3纳米线.     

Controllable Synthesis of WO3 Nanowires by Electrospinning and Their Photocatalytic Properties Under Visible Light Irradiation

Large amounts of WO3 nanowires were prepared on silicon substrates by electrospinning followed by appropriate calcinations in air using ammonium metatungstate(AMT) as WO3 source. Tunable densities and diameters of WO3 nanowires were achieved by changing the electrospinning time and the concentration of AMT in precursor solution.TG/DSC analysis was used to direct the heating process. The effects of both solvent ratio and heating process on the morphology of the obtained nanowires were investigated. The morphology, structure, and chemical compositions of the tungsten oxide were characterized by SEM, XRD, and EDX, respectively. Results showed that monoclinic phase WO3 nanowires with diameters ranging from 100 to 200 nm were obtained after the appropriate heating process when the AMT concentration of the precursor solution increased from 10 to 20 wt%. The photocatalytic performance of the obtained WO3 nanowires under visible light irradiation([420 nm) was investigated in the degradation of Rhodamine B at room temperature in air.     

等离子喷涂ZrC涂层耐烧蚀性能与机理研究

采用等离子喷涂工艺在C/SiC基体材料表面制备了较为致密的W粘结层和ZrC耐烧蚀涂层,利用氧乙炔火焰测试其抗烧蚀性能。结果表明:涂层具有良好的抗烧蚀性能。经烧蚀距离30 mm的氧乙炔烧蚀300 s后,涂层的质量烧蚀率为1.7×10~(-3)g·s~(-1),仅为无涂层试样的68%;线烧蚀率为4.0×10~(-4)mm·s~(-1),仅为无涂层试样的30%。随着烧蚀距离的减小,涂层的质量烧蚀率不断增大,线烧蚀率不断减小。试样表面温度梯度导致涂层存在3种典型烧蚀形貌,中心致密区,过渡区以及边缘疏松区。温度较高的中心区氧化产物为WO_3,其发生熔融并填充涂层内部孔隙和裂纹,形成致密层,且与ZrO_2所产生的协同效应有效降低了机械剥蚀几率,烧蚀以热化学烧蚀为主;温度较低的边缘区烧蚀产物未发生熔融且呈现疏松状,烧蚀主要表现为热化学烧蚀和机械剥蚀。     

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。     

Rietveld分析方法在钨冶金氧化物相定量分析中的应用

用 Rietved分析方法模拟计算钨冶金氧化物相如 WO2 .9、WO2 .72 和 WO3等的标准 X射线衍射 (XRD)谱图 ,并根据多相体模型定量分析法——无标定量相分析确定蓝色氧化钨粉中各相的含量。该法具有简捷方便 ,并能给出全谱概念 ,省时省事 ,有其优越性 ,建议推广应用于钨冶金及硬质合金材料的物相定量分析。     

Effect of monodisperse Cu2S nanodisks on photovoltaic performance of P3HT/PCBM polymer solar cells

Hybrid solar cells using monodisperse Cu₂S nanodisks compositing with the mixture of poly (3-hexylthiophene):1-(3-methoxycarbonyl) propyl-1-pheny [6,6] C61 (P3HT:PC₆₀BM) as the active layer have been fabricated and characterized. The hybrid solar cells exhibit the highest efficiency of 1.35% when the weight ratio of P3HT:PC₆₀BM:Cu₂S is 1:0.8:0.224. The power conversion efficiency (PCE) of nanocomposite device is increased 22.7% comparing with that of the device based on pure P3HT/PC₆₀BM. It is due to that the effect of high-quality Cu₂S nanodisks with good dispersity contributes the increased electronic transportation in the active layer and results in the enhancement in photovoltaic performance. We also investigated the morphology of photoactive layer by microscope; it is found that the dispersity of nanomaterial in active layer is very important for device performance and improvement of carrier mobility.     

Electro-oxidation behavior of tungsten carbide electrode in different electrolytes

The electrochemical activity and stability of tungsten carbide gas diffusion electrode in different electrolytes were determined by galvanostatic charge method. It is shown that WC exhibits good electrocatalytic activity and stability for hydrogen oxidation in acidic solutions when the electrode potential is below about 800 mV (vs DHE), WC is firstly oxidized to an unstable blue tungsten oxides at 800-900mV which are closed to a composite stoichiometry of W2O5 in H2 SO4 solution and W8O23 in HCl solution calculated by charge consumed. Furthermore,the generated intermediate tungsten oxides can be further oxidized into WO3 at higher potentials. While in alkali solution, WC can not be used as anodic catalyst for its poor stability and catalytic activity due to the fact that WC will be directly oxidized into WO3.     

纳米钨/碳化钨粉末的形貌遗传特性及其对粉末均匀性的影响

为研究氧化钨的形貌结构对纳米钨粉末制品均匀性的影响,用X射线衍射分析仪和电子扫描电镜对普通黄钨在660℃下还原的过程产物进行了分析、观测。同时分别以普通黄钨和强力球磨分级处理的细黄钨为原料,采用经优化的工艺条件制备出了纳米W、WC粉末,并对粉末及其快速烧结体的显微组织结构进行了观察、分析。结果表明,不同形貌结构原料制备的纳米W、WC粉末,均呈现出不同程度的形貌结构遗传特性,强力球磨分级处理所获细黄钨颗粒细小、形貌结构疏松,更容易制备出结构较疏松,分散性较好的纳米W、WC粉末。