包覆型氧化铁黄颜料微结构与耐热性能研究

氧化铁黄颜料因耐热性差而限制了在塑料加工和卷材涂料中的应用。本研究以氧化铁黄为前驱体, 采用沉淀法合成氢氧化铝包覆氧化铁黄颜料, 采用XRD、FT-IR、TG-DTA、SEM&EDS和TEM等方法表征包覆型铁黄颜料的结构, 探讨了反应pH对复合材料微结构以及耐热性能的影响。结果表明, pH为4时, 铁黄表面包覆层为无定型氢氧化铝; pH提高至6、8和10时, 表面包覆层为晶态薄水铝石相。包覆后氧化铁黄颜料耐热性有了较大提升。特别在pH为8、10时, 铁黄颜料 240℃下耐热处理30 min后色差值较小, 与表面包覆层形成的薄水铝石相密切相关。铁黄包覆前后, 保持了原先的针状结构, 未出现团聚; 当pH为10时, 包覆后铁黄颜料除针状结构外, 还出现了较粗的晶态棒状物, 可能与羟基氧化铝在反应过程中自身成核有关, 解释了DTA图谱上246℃处出现的特殊吸热峰。本研究为耐温铁黄颜料开发提供了理论与实践指导。     

反应介质对二氧化硅在碳球表面包覆效果的影响

为了改善碳球表面惰性,利用溶胶-凝胶法在碳球表面包覆二氧化硅,考察了介质条件对包覆效果的影响。通过场发射扫描电子显微镜和透射电子显微镜等手段对不同介质中得到的样品进行对比分析表征。结果表明,碱性介质更有利于二氧化硅在碳球表面的包覆,所得复合物球表面光滑、包覆层厚且厚度均一,焙烧除去碳球核后得到空心二氧化硅球,并分析了碳球表面二氧化硅的包覆机理。     

碱土铝酸盐长余辉发光颜料表面包膜的研究

采用四乙氧基硅(TEOS)为硅包膜剂,在SrAl₂O₄:Eu²⁺,Dy³⁺发光颜料颗粒表面进行包膜,通过扫描电镜(SEM)、粒度测量、BET比表面积测试及X射线光电子能谱(XPS)分析,证实发光颜料颗粒表面包覆了一层厚度约为14nm的致密均匀的SiO₂纳米膜.耐水性能及发光性能测试表明,包膜后发光颜料耐水性明显改善,发光性能变化较小.分析表明包膜过程实际上是水合二氧化硅在颜料颗粒表面的溶胶-凝胶过程,其最佳工艺条件为:包膜溶液pH约为10;包膜温度控制在80℃;包膜时间为3.0h.     

TB/TiO2复合白色颜料的微观形态与组成特征研究

介绍了对TB/TiO2复合白色颜料的微观形态与组成特征进行的研究.TB/TiO2复合白色颜料由固体包核物颗粒TB和其表面包覆的结晶TiO2所组成,TiO2在TB表面形成均匀的包覆层.TB/TiO2复合白色颜料因此具有与钛白粉类似的颜料性能.     

金色闪光铝粉颜料的制备研究

本文采用乳液聚合法将聚甲基丙烯酸甲酯(PMMA)包覆在片状闪光铝粉颜料表面,得到了具有金色闪光效果的铝粉颜料.通过扫描电镜(SEM)照片表明在铝粉颗粒表面可形成厚度均匀的PMMA包覆干涉层;通过差热分析(TG)、光电子能谱(XPS)对片状铝粉表面结构进行分析,得出铝粉颗粒表面确实存在PMMA的包覆层且PMMA与铝粉颗粒是以化学键作用相结合.     

一种无机包覆钛酸钾晶须的新方法

利用乙酸乙酯作为均匀沉淀剂在钛酸钾晶须表面成功包覆了SiO2 无机层。利用SEM、FTIR、XRD、EDX等手段对钛酸钾晶须表面包覆层进行了表征和定量分析,并利用Zeta电位仪测试了包覆前后钛酸钾晶须的表面电荷情况。结果表明钛酸钾晶须表面形成了无机SiO2 层,并与晶须表面有一定的相互作用;包覆后晶须表面性质接近于SiO2,有助于钛酸钾晶须进一步表面偶联处理。     

XPS研究Fe2O3纳米粒子表面包覆无机膜

针形铁黄纳米粒子表面包覆无机物如Si、Co等氧化物形成复合纳米粒子,是改善金属磁性记录粉性能的重要方式.采用ICP,TEM,XPS方法研究复合纳米粒子的表面性质,结果表明包硅复合粒子的表面形成均匀、致密的SiO2薄膜,表面层与基体表面间的界面结构类似异质结,导致粒子的XPS谱图中Fe2p谱峰发生2.7eV的化学位移;而包钴复合粒子由于钴在铁黄表面的吸附发生在部分晶面上而无法形成均匀、致密的薄膜,XPS谱图主要发生因表面荷电而导致的物理位移.     

XPS研究Fe2O3纳米粒子表面包覆无机膜

针形铁黄纳米粒子表面包覆无机物如Si、Co等氧化物形成复合纳米粒子，是改善金属磁性记录粉性能的重要方式。采用ICP，TEM，XPS方法研究复合纳米粒子的表面性质，结果表明包硅复合粒子的表面形成均匀、致密的SiO2薄膜，表面层与基体表面间的界面结构类似异质结，导致粒子的XPS谱图中Fe 2p谱峰发生2.7eV的化学位移；而包钴复合粒子由于钴在铁黄表面的吸附发生在部分晶面上而无法形成均匀、致密的薄膜，XPS谱图主要发生因表面荷电而导致的物理位移。     

滑石-TiO_2复合白色颜料的制备及其在涂料中的应用

采用水介质中机械力研磨复合方法制备以滑石为包核、表面包覆TiO_2的滑石-TiO_2复合白色颜料,对复合颜料的性能和结构进行表征,对其在涂料中的应用进行研究。结果表明:复合颜料的颗粒以滑石表面紧密、牢固包覆TiO_2颗粒为特征,粒径分布均匀;复合颜料性能与钛白粉相当,复合60%和70%TiO_2颜料的遮盖力分别达钛白粉的82%和98.9%;添加滑石-TiO_2复合白色颜料15%~20%的涂料涂膜对比率分别≥0.90和≥0.93,达到国标一等品或优等品指标要求,且具有良好的抗紫外老化性能。     

改进的溶胶/凝胶法制备包覆型铝颜料

为提高铝颜料的耐酸及耐碱性,同时保持铝颜料特有的金属光泽,采用改进的溶胶/凝胶法对铝颜料进行了表面包覆,结合FTIR、SEM、TEM、XPS等方法对包覆型铝颜料的微观形貌及包覆层成分进行了分析,并与传统溶胶/凝胶法制备的SiO2包覆的铝颜料的性能进行了对比.结果表明,采用改进的溶胶/凝胶法可以在铝颜料表面形成致密的网状包覆层,从而使其在pH=1的酸性介质及pH=11的碱性介质中的腐蚀保护因子分别达到99.8%和99.9%;与未包覆的铝颜料相比,采用改进的溶胶/凝胶法制备的包覆型铝颜料的光泽度仅下降3.2%,较好地保持了其本身的金属光泽.     

Synthesis of iron red hybrid pigments from oil shale semi-coke waste

Oil shale semi-coke (SC) is a bulk solid waste produced after shale oil being extracted from oil shale. It is abundant on the earth, but most of them are discarded or piled up as solid waste, and their reuse as resources is very limited. In this paper, adhering to the concept of “waste to materials“, the α-Fe₂O₃/SC hybrid pigments with the red color (a* = 29.68) better than commercial iron red pigments (a* = 26.92) were synthesized by an one-pot hydrothermal reaction of pretreated SC with Fe(III), using SC as a cheap starting material. The microscopic structure, chemical composition and color of the hybrid pigments were studied, and the reaction parameters for synthesizing the best hybrid pigments from SC were optimized. The results indicate that the hybrid pigments are mainly composed of SiO₂ and Fe₂O₃, where α-Fe₂O₃ particles grow on the surface of SC-derived silicate substrate with a better dispersion. The hybrid pigments showed a good stability, especially an outstanding high temperature-resistant stability. The secondary heat treatment induced the further improvement of red color value of the hybrid pigments. This work provides a new way and solution for the rational disposal and functional application of SC waste.     

Conformational changes in polymers adsorbed on titanium and iron oxides

The effect of high-energy mechanical processing on the adsorption behavior of the hydrophilic polymer ethyl hydroxyethyl cellulose (EHEC) on the surface of the inorganic pigments TiO₂ and Fe₂O₃ has been studied by IR spectroscopy. High-energy processing of aqueous disperse systems of TiO₂ and Fe₂O₃ activates the surface of the inorganic oxides and promotes polymer adsorption. We present the first evidence that the interaction of EHEC with oxide surfaces is accompanied by conformational changes in the adsorbed EHEC molecules. The conformational transitions depend on the lattice parameters of the inorganic oxides and lead to the formation of special adsorbed solvated EHEC layers, which determine the sedimentation stability of the disperse system.     

天然色素在卷烟纸染色中的影响因素

简述了彩色卷烟纸的现状和前景,并采用天然色素对卷烟纸进行了染色,主要研究染色时的特性.结果表明,pH值的变化对颜色的影响很小,钠盐、锌盐、铝盐、镁盐的加入量对卷烟纸颜色变化影响不大,铁盐的加入对卷烟纸颜色影响较大.抗氧化剂L-抗坏血酸的加入提高了彩色卷烟纸颜色的光稳定性,对湿稳定性也有一定的提高.     

Plasma-chemical synthesis of ultradispersed iron oxides with pigment qualification

The conditions are investigated for preparing ultradispersed iron oxides with pigment qualification (iron oxide pigments) via oxidation in electric arc low temperature plasma (LTP) of: iron dichloride (crystal hydrate), iron sulfate (monohydrate), roughly dispersed iron and burnt pyrites. Using a simplified one-dimensional model, calculations are made describing the motion, heating, melting and evaporation of iron particles of <50 m size; these agree well with experimental results. A procedure is proposed for formation of ultradispersed particle (UDP) structures. Depending on the plasma-chemical process (PCP) parameters, one can control the specific surface (dispersity) of the pigments. The influence is studied of aluminium and aluminium oxide additives on the pigmental properties of iron oxides. Depending on the PCP conditions and the UDP dispersity, the pigment's colour varies from black through dark brown, red-brown, red-violet to light brown. The pigment possesses high surface coverage combined with medium oil absorption and good compatibility with other pigments.     

Synthesis of chromium containing pigments from chromium galvanic sludges

In this work the screening results of the scientific activity conducted on laboratory scale to valorise chromium(III) contained in the galvanic sludge as chromium precursor for ceramic pigments are reported. The valorisation of this waste as a secondary raw material (SRM) is obtained by achievement of thermal and chemical stable crystal structures able to color ceramic material. Two different pigments pink CaCr(0.04)Sn(0.97)SiO(5) and green Ca(3)Cr(2)(SiO(4))(3) were synthesized by solid-state reactions using dried Cr sludge as chromium oxide precursor. The obtained pigments were characterized by X-ray diffraction and SEM analysis. Furthermore the color developed in a suitable ceramic glaze was investigated in comparison with the color developed by the pigments prepared from pure Cr(2)O(3). The characterization carried out corroborates the thermal and chemical stability of the synthesized pigments and, especially for the Cr-Sn pink pigment, the powders develop an intense color that is very similar to the color developed by the pigments obtained starting from pure Cr(2)O(3).     

Hollow iron oxide nanoparticles for application in lithium ion batteries

Material design in terms of their morphologies other than solid nanoparticles can lead to more advanced properties. At the example of iron oxide, we explored the electrochemical properties of hollow nanoparticles with an application as a cathode and anode. Such nanoparticles contain very high concentration of cation vacancies that can be efficiently utilized for reversible Li ion intercalation without structural change. Cycling in high voltage range results in high capacity (～132 mAh/g at 2.5 V), 99.7% Coulombic efficiency, superior rate performance (133 mAh/g at 3000 mA/g) and excellent stability (no fading at fast rate during more than 500 cycles). Cation vacancies in hollow iron oxide nanoparticles are also found to be responsible for the enhanced capacity in the conversion reactions. We monitored in situ structural transformation of hollow iron oxide nanoparticles by synchrotron X-ray absorption and diffraction techniques that provided us clear understanding of the lithium intercalation processes during electrochemical cycling.     

纳米铁黄的表面改性及表征

研究了纳米铁黄有机表面改性的影响因素，确定了最优改性剂和改性条件。采用红外光谱（IR）、热分析（TG）、透射电镜（TEM）和分散性实验对表面改性前后的纳米铁黄进行了表征。实验结果表明，以硬脂酸为改性剂、用量为5％、pH值为4、改性时间为1．5h时，改性后的纳米铁黄的亲油化度达到92．6％。红外光谱和热分析显示，硬脂酸以化学键合的方式结合在纳米铁黄的表面，其质量分数约为4％。透射电镜（TEM）和分散性实验表明，经硬脂酸有机表面改性的纳米铁黄具有亲油疏水性能，能较好地分散于有机溶剂二甲苯中。     

新型无机黄色颜料钒酸铋的研究进展

钒酸铋颜料是一种色泽鲜艳、性能良好、不含铅、无毒的黄色颜料新品种.综述了这类颜料的结构、性质、应用范围,着重介绍了制备工艺、影响因素及其当前的研究进展;同时指出了我国研发钒酸铋颜料的必要性和优越性,并对金属氧化物钒酸铋颜料的研究进展提出了想法.     

Determination of pigments in colour layers on walls of some selected historical buildings using optical and scanning electron microscopy

For successful restoration of painted walls and painted coloured finishing coats it is necessary to determine the composition of the original colour layers. Identification of the pigments used in The Cistercian Abbey of Stična and The Manor of Novo Celje was carried out using optical and scanning electron microscopy. Selected samples of wall paintings were inspected by the combined application of an optical microscope and a low-vacuum Scanning Electron Microscope to determine their colour and structural features and to identify the position of individual pigment grains. Energy dispersive spectroscopy was used to determine the elemental distribution on selected surfaces and elemental composition of individual pigments. It was found that the most abundantly used pigments were iron oxide red, cinnabar, green earth, umber, calcium carbonate white, ultramarine, yellow ochre and carbon black. These identifications have allowed us to compare the use of various pigments in buildings from different historical periods.