朱建育
,
施利毅
,
张仲燕
,
邢建南
,
朱萍
,
华彬
功能材料
以硫酸法钛白的副产物绿矾为原料,采用滴加法制备纳米铁黄(α-FeOOH)颗粒.研究了反应体系的pH值、反应温度、通氧速率、搅拌速率和添加剂等对铁黄颗粒形态结构的影响,采用XRD、TEM等分析手段对颗粒进行表征.结果表明,调节体系pH值能控制铁黄晶型结构和色相;改变通氧速率、搅拌速率、添加剂种类以及反应温度等可以调节纳米α-FeOOH的大小和分散性.
关键词:
纳米颗粒
,
氧化铁黄
,
形态结构
Chinese Journal of Chemical Physics
The formation process of spindle beta-FeOOH particles obtained through the hydrolysis of FeCl3 solutions has been investigated by means of TEM and XRD. The effect of surfactant-Hexadecyl trimethyl ammonium bromide (CTAB) on this process has also been studied. The results show that growth of the needle-like pre-particles is based on the aggregation process, when there is no CTAB in the FeCl3 solution. Once CTAB was added, [beta-FeOOH] nuclies would grow up through the diffusion mechanism. The beta-FeOOH particles were smaller and uniform under the effect of CTAB. The spindle and needle-like beta-FeOOH particles with different axis ratios can be synthesized by controlling the reaction parameters such as the concentration of the original FeCl3 solution and aging temperature.
关键词:
spindle;beta-FeOOH;surfactant;CTAB;formation process;hydrolysis
陈惠玲
,
陈淑慧
,
魏雨
材料保护
doi:10.3969/j.issn.1001-1560.2007.09.008
碳钢在海洋环境锈层中α-FeOOH和Fe3O4易引起高速腐蚀,为探讨其机理,对碳钢在3%NaCl溶液中浸渍和干湿复合循环试验后的锈层进行了红外光谱和扫描电镜分析,提出锈层中的γ-FeOOH和β-FeOOH可自动转化成α-FeOOH和Fe3O4;由γ-FeOOH形成的α-FeOOH和Fe3O4形成速度慢,晶粒小,有保护作用,由β-FeOOH转化而成的α-FeOOH和Fe3O4形成速度快,晶体颗粒大,结构疏松,没有保护作用.
关键词:
碳钢
,
加速腐蚀
,
海洋大气
,
机理
Materials Letters
Tubular alpha-FeOOH was synthesized via hydrothermal reaction at 120 degrees C. X-ray diffraction (XRD) pattern indicates that the as-prepared sample is the pure orthorhombic phase alpha-FeOOH. Fourier transform infrared (FT-IR) analysis further confirms the formation of orthorhombic phase alpha-FeOOH. The morphology and structure of the as-obtained product were characterized by transmission electron microscopy (TEM) techniques. TEM images show a high degree of contrast between the bright central part and the darker edges, demonstrating the hollow core of the product. The obtained tubular alpha-FeOOH was similar to 10 nm in outer diameter and similar to 6 nm in inner diameter, respectively. High-resolution TEM image of one single nanotube shows the clearly resolved interplanar spacing of about 4.18 angstrom, which corresponds to the spacing between (110) planes of the orthorhombic-type alpha-FeOOH crystal. The room-temperature UV-Vis absorption spectrum of the tubular alpha-FeOOH nanostructures is presented. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
tubular;nanomaterials;microstructure;nanotubes;nanoparticles;disulfide;nanowires;nanorods
陈汝芬
,
魏雨
,
人工晶体学报
本文以FeSO4为原料,添加微量EDTA可见光诱导,空气氧化Fe(OH)2?:悬浮液,室温(20 ℃)制备了γ-FeOOH,探讨了各种因素对产物的影响.结果表明:用NaOH作沉淀剂,pH值为8.6,在EDTA作用下可见光诱导有利于低晶γ-FeOOH的生成;pH值在8.0～8.6范围内,随pH值的降低,产物γ-FeOOH的晶化度逐渐提高;用NH3·H2O作沉淀剂,可得到粒径较大的筏状γ-FeOOH.
关键词:
γ-FeOOH
,
合成
,
EDTA
,
可见光
郑晓虹
,
陈力勤
,
沈霖霖
,
陈震
应用化学
doi:10.3969/j.issn.1000-0518.2003.09.013
用还原焙烧法从硫铁矿烧渣中提取铁,制得FeSO4,并以其为原料,在初始铁离子浓度c(Fe2+)为0.15～0.25mol/L、n(Na2CO3)/n(FeSO4)=1的近中性条件(pH值为6～7)下,制备了α-FeOOH晶核;滴加Na2CO3溶液以中和生成α-FeOOH时释放的H+,控制溶液pH值为4～5,使Fe2+以适宜的氧化速率在α-FeOOH晶核的外延生长,制得了均匀性较好的针状α-FeOOH晶体(宽30～40 nm、长约为250 nm).
关键词:
硫铁矿烧渣
,
纳米α-FeOOH
,
碳酸盐法
王燕飞
,
王卫
,
郑遗凡
,
李国华
无机材料学报
doi:10.3724/SP.J.1077.2013.12194
以TiCl4为前驱体,铁黄(α-FeOOH)为载体,采用水解沉淀法在不同温度下制备了系列TiO2/α-FeOOH纳米复合材料.应用XRD、HRTEM、STEM等方法对样品的物相、形貌、微结构等进行系统表征,采用UV-DRS光谱仪检测其光学性能.结果表明:随着反应温度的升高(30℃→90℃),两相形成的包覆结构先逐渐变的连续,然后再逐渐失去连续性,其中45℃反应合成的TiO2/α-FeOOH包覆结构连续致密；包覆外层是由晶粒细小的金红石相TiO2组成,内层由晶粒较大的针铁矿相(α-FeOOH)组成,金红石连续致密地包覆在α-FeOOH外面；TiO2与α-FeOOH之间形成了稳定的共格结构,部分TiO2生长到α-FeOOH外层,晶格畸变变大,复合结构良好.光学性能测试结果表明,包覆结构良好的复合材料吸收峰红移最大,大大拓宽了光谱响应范围,从而有效提高了对太阳光的利用率.
关键词:
金红石
,
铁黄
,
纳米复合材料
,
微结构
Materials Chemistry and Physics
The atmospheric corrosion performance of carbon steel exposed in Warming area, which located in the south part of China with tropic marine environment characters, was studied at different exposure periods (up to 2 years). To investigate the effect of beta-FeOOH on the corrosion behavior of carbon steel in high chloride ion environment, rust layer was analyzed by using infrared spectroscopy, scanning electron microscope, X-ray diffraction, and the rusted steel was measured by electrochemical impedance spectroscopy method. The weight loss test indicated that the corrosion rate of carbon steel sharply increased during 6 months' exposure and gradually reduced after longer exposure. The results of rust analysis revealed that the underlying corrosion performance of the carbon steel was dependent on the inherent properties of the rust layers formed under different conditions such as composition and structure. Among all the iron oxide, beta-FeOOH exerted significant influence. The presence of a monolayer of the rust as well as beta-FeOOH accelerated the corrosion process during the initial exposure stage. EIS data implied that beta-FeOOH in the inner layer was gradually consumed and transformed to gamma-Fe(2)O(3) in the wet-dry cycle, which was beneficial to protect the substrate and reduced the corrosion rate. (C) 2008 Elsevier B.V. All rights reserved.
关键词:
Corrosion;Monolayer;Oxide;Infrared spectroscopy;weathering steel;rust layer;impedance spectroscopy;atmospheric;corrosion;synchrotron-radiation;protective ability;interface;water;iron;temperature
