多功能CeO2/纤维素纳米纤维复合超疏水涂层的制备与性能

自然界超疏水现象因独特的润湿性能被广泛关注,超疏水涂层的制备与应用尤为迫切。采用硝酸铈六水合物(Ce(NO₃)₃·6H₂O)共沉淀法于纤维素纳米纤维(CNFs)表面合成二氧化铈(CeO₂),通过十八烷基三甲基硅氧烷(OTMS)对其进行疏水改性,喷涂构筑得到超疏水涂层。探讨了CNFs、Ce(NO₃)₃·6H₂O和OTMS不同质量比对超疏水涂层形貌和疏水性能的影响。结果表明：CNFs和Ce(NO₃)₃·6H₂O质量比为1∶5和1∶7涂层具有实现超疏水特性的微/纳结构,其中CNFs、Ce(NO₃)₃·6H₂O和OTMS质量比为1∶5∶10涂层接触角为(159.7±1.1)°,滚动角为(5.7±1.8)°,经过150°C高温处理3 h和UV照射36 h后接触角仍大于150°,同时具有良好的p H稳定性和一定的力学...     

聚合物/疏水性SiO2超疏水复合涂层的制备及表征

使用低密度聚乙烯、聚甲基丙烯酸甲酯和疏水性SiO2为原料,通过简单的共混涂膜方法在玻璃基底上制得了具有超疏水性能的聚乙烯/疏水性SiO2和聚甲基丙烯酸甲酯/疏水性SiO2复合涂层;用接触角测量仪、扫描电子显微镜、X-射线光电子能谱仪等分析手段对涂层的润湿性能、微观结构以及表面化学成分等进行了表征。结果表明,所制备的两种聚合物/疏水性SiO2复合涂层的静态水接触角都超过150°,滚动角低至3.0°。聚合物和疏水性SiO2共混涂膜后形成了类似于荷叶的微纳米二元结构,是其表面具有优异超疏水性能的主要原因。     

功能化纳米TiO2/环氧树脂超疏水防腐复合涂层的制备与性能

超疏水材料在金属防腐领域具备巨大的潜在应用前景。为得到疏水性能及防腐性能俱优的纳米TiO₂/环氧树脂复合涂层材料,首先以三甲氧基十七氟癸基硅烷和γ-氨丙基三乙氧基硅烷(KH550)对纳米TiO₂表面功能化;以全氟辛基甲基丙烯酸酯对固化剂二乙烯三氨(DETA)进行氟化;最后通过一步共混法和两步喷涂法分别制备出两种复合涂层。利用FTIR、XPS、1HNMR分析氟化固化剂(F-DETA)和氟化纳米TiO₂(f-TiO₂)的物相组成和组织结构。接触角测试仪和静置实验表明,当三甲氧基十七氟癸基硅烷和γ-氨丙基三乙氧基硅烷的摩尔比为1∶15时f-TiO₂的性能最佳,所制备的复合涂层接触角达到164.9°。SEM表征结果显示通过两步法制备的f-TiO₂/环氧树脂复合涂层具备更均匀的粗糙表面、涂层内部孔隙率较低且环氧树脂层与f-TiO₂层具备梯度结构。摩擦实验证明两步法制备的f-TiO₂/环氧树脂复合涂层的超疏水性具备较好的机械稳定性。Tafel极化曲线和电化学阻抗谱(EIS)研究表明,通过两步法制备的f-TiO₂/环氧树脂复合涂层具有优异的防腐性能,其腐蚀抑制效率高达99.99%。      

环氧树脂/SiO2纳米颗粒复合超疏水表面的制备

利用环氧树脂和纳米SiO₂混合溶液在玻璃基材进行表面成膜,对得到的微米级粗糙结构进行氟硅烷修饰,制备得到具有超疏水性复合膜层。采用扫描电镜、接触角测量仪、高速摄影系统和紫外-可见光谱分析仪进行形貌表征、润湿性表征和膜层透光率测量。结果表明,环氧树脂与纳米颗粒构建的粗糙结构对超疏水表面的构建起到重要作用,该膜层呈现低黏附、低滚动角性能;复合膜层的接触角随SiO₂含量的提高逐渐增大至趋于稳定;复合膜层透光率随SiO₂含量的提高呈现下降趋势,制备膜层的透光率均在75%以上。     

激光熔覆MoSi2颗粒增强Co基涂层的耐磨性能研究

奥氏体不锈钢因低硬度和较差耐磨性限制了其应用,故改善不锈钢表面性能对于促进其应用有重要的工程意义。利用激光熔覆技术制备了不同质量分数(0,20%,40%)的MoSi₂增强Co基合金的复合涂层。采用扫描电镜(SEM)、X射线衍射仪(XRD)、电子探针显微分析仪(EPMA)等方法研究了MoSi₂的添加量对复合涂层的显微组织、相组成、硬度和摩擦磨损性能的影响。结果表明：MoSi₂的加入使复合涂层显微组织柱状晶向等轴晶和平面树枝晶转变,且具有细化组织的效果;随着MoSi₂含量的增加,Co基复合涂层的显微硬度和耐磨性能也随着提高。当MoSi₂的含量为40%时,MoSi₂/Co基复合涂层的显微硬度高达1 455HV_0.2,磨损率为6.9×10^-5 mm³/(N·m);在凝固过程中形成的硬质相(Cr₅Si₃、MoSi₂、Mo₅     

纳米CaCO3/TiO2复合粒子制备超疏水膜

采用溶胶-凝胶法,用γ-(2,3-环氧丙氧基)丙基三甲基氧硅烷和油酸修饰纳米CaCO3/TiO2复合粒子,制备具有类似荷叶表面形貌的超疏水涂层。结合扫描电镜、红外光谱、热重和示差扫描量热仪对复合粒子进行表征。结果表明,纳米TiO2粒子物理复合在纳米CaCO3表面,复合粒子经修饰后引入了疏水性的甲基,形成纳米复合双重粗糙结构,使所制备的涂层表现出优良的超疏水性能,其中接触角为162.1°,滚动角7°。     

SBR-SiO2超疏水涂层的制备与性能

利用羟基硅油(HSO)对白炭黑(SiO2)进行疏水改性,并用过氧化二异丙苯(DCP)对丁苯橡胶(SBR)胶浆进行适度交联,通过粒子填充法制备了超疏水SBR-SiO2涂层。研究了HSO、SiO2和DCP用量及交联条件对涂层成膜性能和润湿性能的影响,探讨了涂层热氧老化和紫外光老化过程中超疏水性能的变化。结果表明,当m(HSO)∶m(SiO2)=1∶1、HSO-SiO2用量为3.5g、DCP用量为0.25g、交联温度为155℃、交联时间为20min时,涂层成膜性能好,接触角为157.0°,且热氧老化和紫外光老化后仍保持较好的超疏水性。扫描电镜照片表明涂层具有微纳米多尺度粗糙结构。     

海泡石超疏水复合涂层的制备和性能

在不同条件下在有机化改性的海泡石粉体悬浮液中加入表面活性剂进行偶联改性,然后进行超声、离心脱水、洗涤、干燥和研磨制得粉体,再使用无水乙醇和分散制成涂料,将涂料涂敷于载玻片表面制备出海泡石超疏水涂层.使用OCA 20接触角测试仪测试涂层与水的接触角(CA)和滚动角(SA),使用BRUKER-80v傅里叶红外光谱仪分析改性...     

SiO_2-PTFE超疏水复合涂层的制备与分析

使用溶胶-凝胶法制备粒径均匀(250nm)、单分散性良好的纳米SiO2微粒,通过控制质量分数配比,将其水溶液与PTFE乳液混合成杂化乳液,后用旋涂法旋涂成膜,在380℃下进行热处理,得到表面形貌与荷叶相似微纳双层结构复合涂层。实验结果表明,用氟硅烷修饰表面后,涂层最高接触角达150.9°,滚动角为8°,具有较好的超疏水性能,且实验制作过程简单,成本低廉,具有一定的实用性。     

羟基硅油改性SiO2制备复合粒子及超疏水涂层的制备与性能

利用羟基硅油的独特性质改性纳米SiO₂制备了一种具有纳米结构的弹性微米级复合SiO₂粒子,并用其与107硅橡胶复合制备出了超疏水涂层。探究了粒子用量对疏水性的影响。使用扫描电镜、接触角测量仪、傅里叶变换红外光谱仪和热失重分析仪对改性后的粒子和超疏水涂层进行表征。结果表明：羟基硅油改性后的粒子与硅橡胶涂料相容性极好,由于粒子表面的硅氧烷分子链能与硅橡胶分子链缠结,且拥有多级粗糙结构的粒子能与固化后的硅橡胶树脂产生机械咬合,因此超疏水涂层拥有良好的机械性能。在40%含量时综合性能最好,疏水角为154.6°,能在500g负载下(约5.4kPa压强),在1000目砂纸上磨损6m仍具有良好的超疏水性。     

纳米CeO2对激光熔覆Fe/Cr3C2复合涂层组织与磨损性能的影响

采用扫描电镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)、显微硬度仪及滑动磨损试验,研究了1%纳米CeO_2(质量分数)对低碳钢表面激光熔覆Fe/Cr_3C_2复合涂层的组织结构和耐磨性能的影响。结果表明,Fe+Cr_3C_2+1%CeO_2复合涂层的主要组成相是α-Fe、γ-Fe、Cr_3C_2、Cr_(23)C_6及Cr_7C_3等化合物相;加入1%纳米CeO_2后,复合涂层组织明显细化,未熔Cr_3C_2数量显著减少,初生碳化物由粗大杆状向块状转变,数量增加,分布均匀,有效抑制和消除了裂纹的形成;复合涂层硬度和耐磨性能显著提高,Fe+30%Cr_3C_2+1%CeO_2涂层截面显微硬度提高105HV,增幅达到15.4%,且涂层沿深度方向硬度分布均匀性得到明显改善。     

Hydrothermal synthesis of CeO2 nano-octahedrons

CeO₂ nano-octahedrons were synthesized with a facile hydrothermal synthesis process where Ce(NO₃)₃·6H₂O and urea were used as a cerium resource and mineralizer respectively and no surfactant or template was applied. The effects of synthesis parameters such as reaction temperature, reaction time, as well as the dosages of Ce (NO₃)₃·6H₂O and urea were studied. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis were conducted to characterize the crystalline and morphology of the obtained CeO₂ powders. The optimal reaction condition to prepare the CeO₂ of the desired fluorite structure was established. The possible mechanism of synthesis of CeO₂ with a nano-octahedron morphology was illustrated.     

Microstructure of YBCO bulk superconductors with CeO2 addition

The refinement of Y₂BaCuO₅ (Y211) particles by CeO₂ in the single-grain YBa₂Cu₃O₇/Y₂BaCuO₅ (Y123/Y211) bulk superconductors of nominal composition Y_1.5Ba₂Cu₃O_x prepared by top-seeded melt-growth process with Y₂O₃ addition has been studied by polarised light microscopy. It is shown that cerium is active in the Y211 particle refinement when it is solved in the peritectic melt, L_p. Observed growth of Y211 particles during sintering stage is ascribed to higher amount of melt induced by CeO₂ reaction with Y123 phase producing barium cerate and CuO.     

Hydrothermal synthesis of monodisperse CeO2 nanocubes

Monodisperse CeO₂ nanocubes have been fabricated via an acrylamide-assisted hydrothermal route. NH₃ and acrylic acid from the hydrolysis of acrylamide act as OH⁻ provider and capping reagent, respectively. The structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and Fourier transformed infrared (FT-IR). The products have a cubic morphology with a mean size of 200 nm. The possible formation mechanism has been discussed based on the experimental results.     

制备参数对花状Au/CeO2催化剂上CO低温氧化性能的影响

采用水热合成法、沉积沉淀法分别制备花球状CeO_2和负载型Au/CeO_2。考察了反应液pH、金的负载量和煅烧温度对Au/CeO_2催化氧化CO活性的影响,确定最佳制备参数,并对优化的Au/CeO_2进行稳定性、储存性和再生性测试。结果表明:反应液的最适宜pH为8.5~9,最适宜的负载量和焙烧温度分别是2%(质量分数)和300℃。优化的Au/CeO_2催化剂,室温下将1%CO催化氧化至1.8×10-6,连续反应67h活性开始下降,当温度升至55℃时,连续反应700h,CO浓度仍然保持在8×10-6以下。此外,该催化剂还表现出良好的储存性和再生性。     

CeO2掺杂制备Ba0.9Ca0.1Ti1-xSnxO3压电陶瓷的结构及电性能

采用传统的陶瓷烧结技术,通过添加0.15%(摩尔分数)CeO2,在1120℃烧结2h,成功制备了新型无铅压电陶瓷Ba0.9 Ca0.1 Ti1-x Snx O3,并且检测了陶瓷样品的微结构和电性能.XRD显示所有陶瓷样品均具有纯的钙钛矿结构,在室温下为典型的四方相,SEM显示适量添加锡离子可以提高陶瓷致密性.在室温下,锡离子改性的BaTiO3基压电陶瓷在x=0.02处显示了优异的压电、介电和铁电性能(d33=276 pC/N,kp=46%,εr=3678,tanδ=2.4%,Pr=18.2μC/cm2,EC=1.12 kV/mm).这些优异的检测结果证实适当添加锡离子能改善BaT iO3基压电陶瓷的电性能.     

Infrared to visible upconversion luminescence in Er/Yb co-doped CeO2 inverse opal

Infrared to visible upconversion luminescence has been investigated in Er³⁺/Yb³⁺ co-doped CeO₂ inverse opal. Under the excitation of 980 nm diode lasers, visible emissions centered at 525, 547, 561, 660 and 680 nm are observed, which are assigned to the Er³⁺ transitions of ²H_11/2 → ⁴I_15/2 (525 nm), ⁴S_3/2 → ⁴I_15/2 (547, 561 nm), ⁴F_9/2 → ⁴I_15/2 (660 and 680 nm), respectively. The effect of photonic band gap on the upconversion luminescence intensity was also obtained. Additionally, the upconversion luminescence mechanism was studied. The dependence of Er³⁺ upconversion emission intensity on pump power reveals that it is a two-photon excitation process.     

大比表面积、高孔隙率多孔仿生CeO2-CuO光催化剂

以富含多孔结构的纤维素为诱导体,采用浸渍法制备仿生CeO_2-CuO催化材料,通过X射线衍射(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附-脱附(N2adsorption-desorption)、紫外-可见漫反射光谱(UV-vis)等分析手段对产物的结构和形貌进行了表征。在可见光条件下,以亚甲基蓝溶液为模拟废水,测试其TOC(Total organic carbon)去除率,并对光催化降解机理进行探讨。实验结果表明所制备的材料颗粒均匀,平均颗粒尺寸在10nm左右,并且含有丰富的介孔结构,其孔径集中分布于5~10nm。由紫外-可见漫反射吸收光谱可知,材料对可见光的吸收程度高于块状氧化铈,从而具有更高的可见光催化活性,光照2.5h后对亚甲基蓝的TOC去除率为90%。     

Interaction mediated by size differences between Y2BaCuO5 and CeO2 particles in melt-textured YBCO superconductors

The Refining of Y₂BaCuO₅ (Y211) is crucial in the fabrication of YBa₂Cu₃O_x (Y123) bulk superconductors with a high critical current density (J_c) for power engineering applications.In this work, the influence of an addition of Y211 and CeO₂ of different sizes on the Y211 refinement and superconducting properties of melt-textured Y123 superconductors is investigated. Nano-size Y211 and nano-size CeO₂ were prepared by attrition-milling (250 rpm and 2 h). Using mixed powders consisting of 85 wt.% Y123, 15 wt.% Y211, and 1 wt.% CeO₂, Y123 quasi-single crystals were fabricated via a top seed melt-textured growth process. The interaction between Y211 and CeO₂ of different particle sizes was examined in terms of the size, uniformity and density of the Y211 particles that existed in the melt-textured samples. The reaction between the nano-size Y211 and the nano-size CeO₂ was more violent due to the more frequent collisions compared to the other reactions (micro-size Y211/nano-size CeO₂ or micro-size Y211/micro-size CeO₂), resulting in the most effective for refinement of Y211 particles and the best J_c value of 4.2 × 10⁴ (A/cm²) (at 77 K and a zero-field).     

Synthesis of ordered mesoporous CuO/CeO2 composite via co-nanocasting replication method and its improved reactivity towards hydrogen

Ordered mesoporous CuO/CeO₂ composites with cubic Ia3d or 2-D hexagonal p6mm structure have been synthesized by a co-nanocasting-replication method using mesoporous silica KIT-6 or SBA-15 as hard template. XRD, TEM, N₂-adsorption and H₂-TPR techniques were used for the structural analysis and catalytic activity characterization. The results indicated that the high surface area mesoporous CuO/CeO₂ composites with different amounts of CuO addition were well-crystallized and exhibited much improved reactivity towards hydrogen than pure mesoporous CeO₂, and the CuO/CeO₂ composite with 20 wt.% CuO addition possessed the highest reactivity towards hydrogen. The enhanced H₂-TPR property could be attributed to the synergetic catalytic effects between copper oxide and cerium oxide.