SiO2—TiO2—ZrO2系涂层的制备及其特性

用溶胶－凝胶法（sol-gel method）在不锈钢表面制备了SiO2-TiO2-ZrO2系无机氧化膜（STZ）。用DTA／TG、IR、XRD和SEM等手段研究了涂层制备时由凝胶向玻璃态的转变以及涂层薄膜的显微结构特点，考察了涂层对基体的保护效果。试验结果表明，在溶胶至凝胶最终转变为无机氧化物的过程中形成了无机网络，Si^4 和Zr^4 充当了网络骨架的形成离子。涂层为无定型玻璃态，其间混有石英、锐钛矿或金红石等微晶。     

溶胶-凝胶法聚氧乙烯(PEO)掺杂的TiO2薄膜的制备

本文以钛酸四丁酯Ti(OBu)4为原料,用溶胶-凝胶方法在ITO玻璃上制备了均匀透明的聚氧乙烯(PEO)掺杂的PEO-TiO2有机-无机复合涂层,研究了相关的制备参数,并对涂层进行了电化学循环伏安测试及着、褪色态可见光透过率测试,结果表明:PEO小于2mg/ml时,溶胶具有较好的稳定性,在此范围内,随PEO掺量的提高,薄膜的可见光透过率显著提高,同时,PEO-TiO2膜较TiO2膜具有较强的离子注入/退出能力、较高的循环可逆性和电荷容量.     

金属表面复合保护涂层的制备与性能研究

采用溶胶-凝胶法合成了有机-无机复合溶胶.用提拉法将复合溶胶涂覆在不锈钢基板上,基板上的湿凝胶经热处理后便形成了透明保护涂层.对制备好的涂层进行了附着力和硬度等性能分析,分析结果表明:有机-无机复合溶胶易于成膜,且成膜具有很好的耐磨性、韧性和耐腐蚀性.     

溶胶—凝胶法制备有机改性SiO2—TiO2涂层的研究

用溶胶－凝胶法在ＰＭＭＡ上制得ＳｉＯ２－ＴｉＯ２涂层。溶胶粘度分析表明，溶胶以线性生长方式凝胶，适宜于制备薄膜。ＦＴＩＲ对涂层的干燥和热处理过程研究表明，涂层中形成Ｓｉ－Ｏ－Ｔｉ－Ｏ－Ｓｉ无机网络结构。扫描电镜对涂层中Ｔｉ－Ｓｉ元素的分布进行了能谱分析，发现无机网络主要分布于涂层的表面及界面处。     

金属表面复合保护涂层的制备与性能研究

采用溶胶-凝胶法合成了有机-无机复合溶胶。用提拉法将复合溶胶涂覆在不锈钢基板上，基板上的湿凝胶经热处理后便形成了透明保护涂层。对制备好的涂层进行了附着力和硬度等性能分析，分析结果表明：有机-无机复合溶胶易于成膜，且成膜具有很好的耐磨性、韧性和耐腐蚀性。     

ZrO2@Al2O3陶瓷涂层耐蚀性能研究

用溶胶－凝胶（sol-gel)法在不锈钢表面制备xZrO2.yAl2O3陶瓷涂层,用X射线衍射（XRD）和扫描电子显微镜能谱仪分析了涂层组成与结构;用金相显微镜观测了涂层的孔隙率;用浸泡法和高温抗氧化性试验研究了涂层的耐腐蚀性能。结果表明：xZrO2.yAl2O3涂层随二组分含量的趋近,结构从晶态转变成微晶与玻璃态混合组成,直至完全的玻璃化,涂层致密度提高,耐高温和耐腐蚀性能依次增强。     

溶胶-凝胶法制备的Ti/IrO2+Ta2O5阳极涂层性能

热分解法制备的涂层性能不够理想,现更多采用溶胶-凝胶法,但传统溶胶-凝胶法制备阳极仍存在工艺复杂、可操作性差的缺点.从电极的前驱体入手,将贵金属的无机盐制备成有机盐,采用溶胶-凝胶法制备了Ti/IrO2+Ta2O5阳极涂层,并与热分解法制备的涂层进行了对比研究.经SEM,EDX,循环伏安,电化学阻抗谱及强化电解寿命试验表明,与热分解法相比,由溶胶-凝胶法制备的氧化物阳极涂层表面呈现较多的龟裂纹,且有少量氧化铱晶簇析出,其电化学活性表面积增大,提高了电极的电催化活性,但稳定性降低.     

有机硅溶胶-凝胶防腐蚀涂层研究进展

有机硅溶胶-凝胶涂层是指以烷基烷氧基硅烷为前驱体通过溶胶-凝胶技术制备的涂层。有机硅是分子水平上的有机-无机杂化分子,因此有机硅溶胶-凝胶涂层兼具了有机材料和无机材料的性能,并且能通过合理的调控有机和无机成分来获得所需的性能。其热稳定、耐刮擦性与无机材料的结合性能明显高于普通的有机材料,柔韧性与有机材料的结合性能明显高于一般的无机涂层。近年来,这种新型的、具有特殊性能的涂层被广泛研究用来保护金属材料(如铝、铁、镁、铜基材料)。介绍了有机硅溶胶-凝胶涂层涉及的基本反应、硅烷在金属表面上的成键机理以及在不同金属上的应用等方面的研究进展,并展望了有机硅溶胶-凝胶涂层应用前景及未来的研究方向。     

铝合金表面防腐蚀处理新工艺

为避免铬酸盐处理铝合金造成环境污染,以环境友好的γ-缩水甘油醚丙基三甲氧基硅烷(GPTMS)和正硅酸乙酯(TEOS)为原料,用溶胶-凝胶法在室温下制备有机-无机杂化溶胶,经浸涂并室温固化后在铝合金表面形成涂层.通过X射线衍射、反射吸收红外光谱、腐蚀测试技术(盐雾试验和动电位扫描)和标准胶带方法对涂层的结构、耐腐蚀性及粘结力进行了分析和测试,结果表明,由于形成了致密的非晶态涂层,同时涂层和基体界面之间形成了稳定的Ai-O-Si化学键,该涂层具有优异的耐腐蚀性能和强的结合力.     

TEOS/OTMS超疏水涂层的制备及形成机制

以正硅酸乙酯(TEOS)和正辛基三甲氧基硅烷(OTMS)为原料,采用溶胶-凝胶法制备了TEOS-OTMS溶胶,分别在光滑玻璃基体、刻蚀玻璃基体上,通过一步浸渍提拉法制备了疏水涂层,研究了水解时间对涂层疏水性能和硬度的影响,提出了TEOS-OTMS溶胶与疏水涂层形成机制。结果表明：TEOS-OTMS原位水解-聚合可以制备以SiO₂颗粒为胶核,辛基硅烷包覆的胶体粒子,在玻璃基体形成辛基链修饰的低表面疏水膜层,当TEOS预水解聚合4 h, TEOS-OTMS共水解聚合20 min时,涂层疏水角达到(124.01±2.00)°,铅笔硬度达到6 H。利用扫描电子显微镜对微观结构进行分析,玻璃基体通过刻蚀形成间距6.36 nm、平均大小16.75 nm的微观凸起,使TEOS与OTMS的缠结、聚集增强,涂层形成了150～200 nm的孔隙,这种“微观粗糙”是形成超疏水涂层的关键,TEOS-OTMS涂层疏水角达到(160.08±2.00)°。     

VLE data for CO2-CF2Cl2, N2-CO2, N2-CF2Cl2 and N2-CO2-CF2Cl

Knowledge about vapour-liquid (VLE) is required as a basis of reliable calculations for separation processes. Correlations available for the prediction of T, p, x, y data are less accurate for mixtures at high pressures and mixtures containing supercritical components. The results of VLE experiments are reported and compared with data calculated with equations of state.     

Thermal diffusion in binary mixtures H2-CCl2F2 and H2-CHClF2

Thermal diffusion coefficients were measured in two gaseous mixtures, in which one component was close to the critical temperature, in the pressure range (19.6–127.4)·10⁴ N/m² and at a freon concentration of 0.25–0.8.     

Preparation of ZrO2-CeO2 and HfO2-CeO2 nanopowders

We prepared weakly agglomerated powders of ZrO₂-CeO₂ and HfO₂-CeO₂ solid solutions 5–8 nm in particle size, consisting of monoclinic and tetragonal phases. After heat treatment at 1200°C, the crystallite size was 30 and 14 nm, respectively. We also examined the effect of precipitate freeze drying on the crystallization of hafnia-based solid solutions containing up to 20 mol % CeO₂.     

Comparison of the Electronic Structures of La2CuO4, Sr2CuO2Cl2, and Sr2CuO2F2

First-principles cluster calculations are reported of the local electronic structure of the three compounds: La₂CuO₄, Sr₂CuO₂Cl₂, and Sr₂CuO₂F₂. The copper ${\text{3d}}_{x^2 - y^2 } $ and the planar oxygen 2p _σ atomic orbitals exhibit a similar degree of covalency. The out-of-plane orbitals, however, are quite different with the ${\text{3}}d_{3z^2 - r^2 } $ atomic orbital lowered significantly in energy for chlorine and fluorine apical positions.     

Radial GRIN glasses in Li2O-Na2O-Al2O3-TiO2-SiO2 systems

A series of GRIN glass rods have been developed in Li2O-Na2O-Al2O3-TiO2-SiO2 systems. Negative radial refractive index profiles were generated by exchanging Na+ for Li+ ions in these glass rods. It has been observed that TiO2 plays a vital role in increase in the profile depth and maximum change in the refractive index because of its ambivalent nature. Change in the refractive index can be further increased by increasing the concentration of exchanging cation in the base glass.     

Elastic and Electronic Properties of Superconducting CaPd 2 As 2 and SrPd 2 As 2 vs. Non-superconducting BaPd 2 As 2

The first-principles calculations were performed to predict the elastic and electronic properties of the superconducting ThCr₂Si₂-type phases CaPd₂As₂ and SrPd₂As₂ in comparison with the non-superconducting CeMg₂Si₂-type phase BaPd₂As₂. Besides, the same properties were compared for CeMg₂Si₂- and ThCr₂Si₂-type polymorphs of BaPd₂As₂. We found that all these phases are mechanically stable and belong to soft materials with low hardness. The near-Fermi region is formed by the valence states of the blocks [Pd₂As₂] with decisive contributions of Pd 4d states. The values of N(E _F) increase in the sequence: CaPd₂As₂ < SrPd₂As₂ < BaPd₂As₂, i.e. in the reverse sequence relative to the transition temperatures T _C. Thus, the change in T _C cannot be explained by the electronic factor, i.e. by the simple correlation T _C～N(E _F). Most likely the decrease in T _C in the sequence CaPd₂As₂ → SrPd₂As₂ and the absence of a superconducting transition in BaPd₂As₂ are related to the structural factors and the peculiarities of the electron–phonon coupling mechanism.     

Si_2N_2O-Al_2O_3-La_2O_3和Si_2N_2O-Al_2O_3-CaO系统的亚固相关系

本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O