sol-gel法制备NiZn铁氧体透明薄膜研究

采用溶胶-凝胶法制备NiZn铁氧体薄膜,研究了溶胶配制、甩胶及退火工艺对NiZn铁氧体薄膜性能的影响,系统研究了制备工艺和退火工艺。结果表明,不同的膜厚,改变了样品内的残余应力;在退火工艺上,升温速率直接影响成核数量,退火温度和保温时间决定薄膜的结晶程度和附着力的大小。通过对溶胶-凝胶法制备NiZn铁氧体薄膜技术的研究及工艺优化,得到合理的退火处理工艺为:以2.5℃/min的升温速率升到700℃,保温40 min后随炉自然冷却到室温。同时研究了NiZn铁氧体薄膜的可见光透过和微波损耗特性。     

制备工艺和添加剂对NiZn铁氧体薄膜性能的影响

Ni Zn铁氧体薄膜具有优良的软磁特性、良好的机械耐磨性、稳定的化学性能、较高的铁磁共振频率和高电阻率等诸多优点,已成为铁氧体薄膜领域重要的研究方向。结合通讯系统器件发展趋势,本文对Ni Zn铁氧体薄膜材料的性能研究及应用进行了介绍,着重从薄膜的制备技术和添加剂等方面综述了当今国内外对Ni Zn铁氧体薄膜研究现状及最新研究进展,并指出了今后Ni Zn铁氧体薄膜研究的主要方向。     

NiZn铁氧体生产工艺的研究

随着电子产业的发展,对NiZn铁氧体的性能提出了越来越高的要求。行内人士从NiZn铁氧体工艺的各个方面进行研究和改善,制定出效率更高的工艺设计,制造出性能更好的产品。文章将对NiZn铁氧体材料的原料、添加剂和粉料制备、成型、烧结等生产工艺进行综合论述。     

EDTA络合溶胶-凝胶法制备Mn-Zn铁氧体

以铁、锰、锌的硝酸盐和氨羧络合剂乙二胺四乙酸二钠(EDTA)为原料,采用有机配合物络合溶胶-凝胶法成功制备出纳米晶锰锌铁氧体材料.用X-射线衍射仪(XRD)、差热重量分析仪(TG/DTA)、扫描电镜(SEM)和振动样品磁强计(VSM)对不同条件下所制备产品的晶型、晶貌及磁性能进行了表征.结果表明:EDTA络合溶胶-凝胶法能在pH=4,煅烧温度为773 K,煅烧时间为2 h条件下制备出结晶性良好、粒径在30 nm左右的纳米晶锰锌铁氧体;制备过程中添加分散剂乙二醇(EG)能够有效加速有机物分解,并能有效减轻晶粒间的团聚,使材料的矫顽力显著降低.     

柠檬酸溶胶-凝胶法制备钡铁氧体

应用sol-gel技术制备纳米钡铁氧体,研究了3种不同的sol-gel制备工艺对钡铁氧体生成过程的影响.研究结果表明,影响sol-gel制备的因素有:温度、pH值和柠檬酸用量、助剂、杂质的处理及溶胶回流的选择;钡铁氧体晶体的平均粒径、结晶形状,分布,团聚程度都影响其磁性质.3种实验方法均可制得高纯度BaFe12O19(简称BaM)磁性材料.在3种方法中,工艺Ⅲ的综合性能最好,在900℃得到钡铁氧体平均粒径为155nm,其比饱和磁化强度M,=58.78Am2/kg,矫顽力Hc=407.9kA/m.     

溶胶-凝胶法制备薄膜

综述了溶胶-凝胶法制备薄膜材料的一般原理及工艺步骤。并对其应用做了一定的展望。     

二氧化钛纳米薄膜溶胶-凝胶法制备研究

研究了在清洁的玻璃表面采用溶胶-凝胶法制备锐钛矿相二氧化钛纳米薄膜,重点研究了薄膜制备过程中的关键工艺如溶胶配制及其稳定性、溶胶陈化及胶粒长大、提拉法涂膜次数及是否添加稳定剂对薄膜表面形貌均匀性的影响等.对所制备的薄膜的X射线衍射、光学显微镜、扫描电子显微镜及能谱分析表明,该薄膜为典型锐钛矿相二氧化钛,薄膜中二氧化钛纳米颗粒分布均匀、致密,纳米颗粒大小分布窄,直径约为30 nm,薄膜厚度约为300 nm.     

溶胶-凝胶法制备NiO薄膜及影响因素

NiO薄膜可作为电致变色材料、电容器材料、气敏材料、电极材料等而受到人们关注。溶胶凝胶法(sol-gel)制备NiO薄膜材料因其无可比拟的优点成为研究的热点。简要介绍了sol-gel法制备NiO薄膜的特点及基本原理,重点论述了成膜方式、溶胶性质以及热处理条件对薄膜形貌、结构和电化学性能的影响,展望了NiO薄膜材料的发展方向,旨在为NiO薄膜材料的研究和开发提供一些借鉴和启发。     

溶胶-凝胶法制备疏水型SiO2薄膜的研究

采用溶胶-凝胶工艺,以正硅酸乙酯（TEOS）为前驱体,结合三甲基氯硅烷（TMCS）对胶粒的修饰作用,利用浸渍提拉法在玻璃表面制备了具有一定疏水能力的SiO2薄膜.考察了TMCS的掺杂量、醇硅比、加水量及热处理温度对薄膜疏水性的影响.     

Characterization of submicrometer-sized NiZn ferrite prepared by spark plasma sintering

High-density submicrometer-sized Ni_0.5Zn_0.5Fe₂O₄ ferrite ceramics were prepared by spark plasma sintering in conjunction with sufficient high energy ball milling. They were evaluated by different characterization techniques such as X-ray diffraction, scanning electron microscopy, and dielectric and magnetic measurements. All samples prepared at sintering temperatures ranging from 850 to 925 °C exhibit a single spinel phase and their relative densities and grain sizes range from 90% to 99% and ~100 nm to ~300 nm, respectively. The dielectric constant increases with decreasing grain size until ~250 nm, and then decreases dramatically with further decreasing grain size. The saturation magnetization increases continuously with increasing grain size/density but the magnetic coercivity decreases. The highest dielectric constant and saturation magnetization at room temperature are approximately 1.0×10⁵ and 84.4 emu/g, respectively, while the lowest magnetic coercivity is only around 15 Oe. These outstanding properties may be associated with high density and uniform microstructure created by spark plasma sintering. Therefore, the spark plasma sintering is a promising technique for fabricating high-quality NiZn ferrites with high saturation magnetization and low coercivity.     

Effects of aqueous ethanol solutions on the structural and magnetic properties of NiZn ferrite thin films prepared by spin-spray deposition

Although substrate wettability greatly impacts deposition processes using the spin-spray technique, there are few substrates suitable for the deposition of spin-sprayed ferrite thin films. To tune substrate wettability without changing the type of substrate, we demonstrate a Ni_0.17Zn_0.52Fe_2.31O₄ ferrite film deposited by the spin-spray technique on a 0.2 mm glass substrate with 0–5% aqueous ethanol solutions. All samples showed (222) preferential orientation and triangular grain morphology. The effects of aqueous ethanol solutions on the microstructure and magnetic properties of ferrite thin films were also investigated. When the ethanol volume percent concentration equaled 3%, the columnar morphology of the microstructure was most evident and the saturation magnetization and the real permeability reached their maximum values. Because of the shape anisotropy of the columnar structure, the coercivity of the parallel magnetic field increased, whereas the coercivity of the perpendicular magnetic field decreased. First-order inversion curve measurements revealed that ethanol-containing ferrite thin films had a more uniform grain size.     

Photochemical diodes of a TiO2 film prepared by a sol-gel method

Photochemical diodes were prepared using a thin film of TiO₂ made from titanium isopropoxide by a sol-gel method. A half part of a conductive SnO₂ film plated on a quartz plate was coated with the TiO₂ film, and the other parts of the SnO₂ substrate were coated with a thin Pt film. The photochemical diode thus prepared shows photocatalytic activity for hydrogen evolution from aqueous ethanol solutions containing NaOH or HClO₄. No other products are detected in the gas phase. Hydrogen evolution from the Pt part is definitely observed, indicating electron transfer from the TiO₂ film to the Pt film through the SnO₂ film. Another type of photochemical diode, the TiO₂ film coated on a Pt plate, is found to show higher activity than the TiO₂/SnO₂/Pt device for the hydrogen photo-evolution without any support electrolyte. Hydrogen evolution on this device, however, occurs on the TiO₂ side but not on the Pt side. These results are discussed in terms of a photo-electrochemical mechanism at semiconductor surfaces.     

Hydrophobic hybrid inorganic-organic thin film prepared by sol-gel process for glass protection and strengthening applications

Hybrid systems based on 3-trimethoxysilyl propyl methacrylate, tetramethylorthosilicate, and methyl methacrylate were developed for moisture protection and strengthening of glass objects. The hydrophobic behavior of the hybrid was obtained by adding different fluorinated precursors to the hybrid solution. Experimental results show that among different fluorinated percursors, 1H,1H,2H,2H-perfluorooctyl trichlorosilane gives the best results, increasing the water contact angle up to 100° and decreasing the free surface energy. Coated glasses exhibit higher strength (more than 50%) than uncoated glasses. The strengthening was interpreted in terms of a healing mechanism. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2387–2393, 1997     

Crystallisation kinetics of hydroxyapatite thin films prepared by sol-gel process

Abstract

Abstract

In this study, the crystallisation of nano hydroxyapatite (HA) films on stainless steel 316L was studied. The film was prepared by sol-gel technique. The process was started with preparation of an HA sol. After aging of the sol at room temperature, a stainless steel 316L substrate was dip coated and then was heat treated from 350 to 450°C at different periods of time in air. The crystallisation behaviour and the transformation-temperature-time diagram of HA films were achieved and analysed using the avrami equation. The results showed that the crystallisation of HA began at 250°C and was increased up to 450°C. The obtained HA film showed a nanostructure character with a suitable crystalinity after heat treatment.     

溶胶-凝胶法制备二氧化钛薄膜的研究进展

光催化净化空气是一项造福人类的绿色环保技术。TiO₂薄膜化是光催化技术实用化的关键。介绍了近几年来溶胶-凝胶法制备TiO₂薄膜光催化净化空气的研究进展,对溶胶-凝胶法制备TiO₂薄膜的各种影响因素进行了分析,并探讨了提高TiO₂薄膜光催化能力的途径及其相关的光催化反应系统。     

溶胶-凝胶法制备二氧化钛及其光催化降解氰根的研究

以NaCN水溶液模拟含氰废水,探讨了TiO2对CN-降解率的影响因素,结果表明,在pH=4,CN-初始浓度为10 mg/L,TiO2用量为1 g/L,反应时间为12 h时,CN-降解率可达99.5%。     

CTAB对溶胶-凝胶法制备纳米ZnO形貌的影响

以醋酸锌、草酸为主要原料,采用溶胶-凝胶法制备纳米ZnO。在反应体系中加入表面活性剂十六烷基三甲基溴化铵(CTAB),成功制得短柱状及棒状结构的纳米ZnO。借助XRD和TEM对产物的结构和形貌进行了表征。结果表明,产物属于纤锌矿结构的六方相ZnO,并且,在棒状结构纳米ZnO的形成过程中CTAB起关键作用,改变反应体系中CTAB的加入量,可以实现纳米ZnO的形貌控制合成。讨论了棒状纳米ZnO可能的形成机理。