强碱-阳极氧化法处理Ti片制备TiO_2薄膜的研究

本文利用强碱-阳极氧化法对钛片进行改性,制备TiO2薄膜;用扫描电镜（SEM）、X射线光电子能谱（XPS）考察了不同电解液浓度下氧化电压对TiO2氧化膜形貌及组成的影响。结果发现,在本实验条件下,该法制得的氧化膜是由三种钛氧化物组成的,主要成分是TiO2,此外还有低价钛氧化物Ti2O3及TiO;氧化电压的不同会对薄膜形貌产生重要的影响,当氧化电压较高时,氧化膜的厚度比较厚且致密;钛表面生成氧化膜大致过程可概括为：Ti→TiO→Ti2O3→TiO2,其中TiO转为为TiO2的几率依靠电势的大小及氧化时间的长短。     

Oxidation behavior of Ti3SiC2 powder synthesized by using biochar,Si and Ti

Biochar was proposed as a novel carbon source for synthesizing Ti₃SiC₂ powder with high purity by a simple pressureless sintering at 1673 K, and Ti₃SiC₂ grains exhibited the typical nanolayered structure. The oxidation behavior of Ti₃SiC₂ powder showed the parabolic law during isothermal oxidation from 1273 K to 1473 K. Dense and continuous oxidation layer consisting of mixed TiO₂ and SiO₂ was formed rapidly on the surface of Ti₃SiC₂ particles as a diffusion barrier, which effectively retarded the inward diffusion of oxygen, conferring good oxidation resistance of the powder.     

钛表面阳极化处理技术

通过对一台钛制设备阳极化处理工艺过程的详细介绍、氧化膜性能的考察及设备的跟踪调查,证明了阳极化处理后能提高钛制设备的硬度、耐磨性、耐蚀性和绝缘性。     

用MOCVD方法制备TIO2薄膜：工艺及进展

本文概述了用金属有机物化学气相沉积（ＭＯＣＶＤ）的方法制备了ＴＩＯ２薄膜的原理工艺过程用工艺特点，并指出了最新研研进展和存在的问题以今后及发展方向。     

Nanostructuring of NiAl-Mo eutectic alloys by selective phase dissolution

A technique for the electrochemical structuring of directionally solidified NiAl-Mo eutectic by selective phase dissolution is presented. Local matrix dissolution at 200 mV SHE in 1 M HCl of pH 1 yielded the grid of Mo nanowires spanning along the central part of the sample. On the other hand, the dissolution of the fibrous minor phase while passivating the continuous NiAl matrix resulted in continuous nanopore arrays. Initially, mechanical polishing and electropolishing were employed to thin the samples. Etching time was optimized by plotting the etch time until hole formation as a function of initial sample thickness, along with plotting sample thickness versus etching time. As a next step, an investigation into the passivation behaviour of the NiAl was performed in order to determine the optimal potential for wire dissolution. A potential scan from 0 to 2500 mV SHE on a bulk sample of pure NiAl in an electrolyte of 0.1 M acetate buffer pH 6.0 indicated that a potential of 500 mV SHE, just below the breakdown potential would provide maximum driving force for wire dissolution process. Different parameters within the electrochemical system are varied in order to optimize the wire dissolution. The extent of wire dissolution is measured both quantitatively (total charge transfer) and qualitatively (optical and SEM imaging).     

阳极氧化制备氧化钛薄膜机理探讨

在钛合金表面采用阳极氧化工艺制备出氧化钛薄膜.通过实验验证了阳极氧化原理,得出在不同的氧化电压下可生成不同厚度的氧化钛薄膜,薄膜越薄呈色越鲜艳;并分析了阳极氧化电解液对形成薄膜的影响;最后模拟分析了氧化薄膜的生长过程.     

电流密度对Ti 6Al 4V微弧氧化膜形貌和性能的影响

采用NaAlO2-Na3PO4-NaF溶液体系,研究了电流密度对Ti 6Al 4V合金微弧氧化膜厚度、生长速率、表面形貌、粗糙度、组成相以及氧化膜耐蚀性、耐磨性等影响.结果表明,(1)在试验的电流密度范围内,氧化膜的厚度随电流密度的增大呈线性增大,但氧化膜的粗糙度却几乎呈指数增大,表面质量变差;(2)在质量分数为3.5%的NaCl溶液中显示了比Ti 6Al 4V钛合金更好的耐蚀性;(3)在干摩擦条件下,氧化膜的摩擦系数高于基体的,氧化膜的磨损机制为脆性断裂.     

铝硅合金热氧化膜层耐电化学腐蚀性能

采用SEM、全浸渍、色度测试等测试方法研究铝合金热氧化法制得氧化膜层表面形貌和耐蚀性能。结果显示:氧化后,耐蚀性明显增强,并且氧化温度越高,得到的氧化层耐蚀性越好;相同温度下,随着氧化时间的延长,耐蚀性越好,氧化8 h后继续氧化,耐蚀性趋于稳定;在纯氧中氧化的耐蚀性优于在空气中氧化;耐蚀性好的膜层表面偏灰,略成黄色。     

Microstructure Evolution of Pulsed Laser-Deposited (Ba, Sr)TiO3 Films on MgO for Microwave Applications

To develop low-loss tunable microwave circuits, based on the field dependence of dielectric permittivity, phase pure (Ba_0.5, Sr_0.5)TiO₃ doped with 1% W (BST) thin films 0.3-μm thick were deposited on single crystal MgO wafers by pulsed laser deposition. The BST films were characterized by X-ray θ–2θ scans and pole figure analysis, field emission scanning electron microscopy (FESEM), and cross-sectional transmission electron microscopy (TEM), coupled with selected-area electron diffraction (SAED). Although, the X-ray θ–2θ scan indicated an epitaxial nature of BST with an out-of-plane orientation of (100), the pole figure analysis confirmed the presence (4–6%) of (111)-oriented grains in a matrix of (100) textured grains. The columnar grains exhibited an in-plane (i.e., along the plane perpendicular to the growth direction) grain size that was thickness-dependent. The cross-sectional TEM, coupled with SAED in the thickness direction, corroborated the pole figure analysis. Additionally, from X-ray analysis, it was observed that the textured films were under in-plane tension. The deposited film was characterized at microwave frequencies (1–20 GHz) using interdigitated electrodes deposited on top of the film. The film was characterized by a relatively low dielectric Q of 5–7. A 17% change in the capacitance was observed when applying a 40 V bias. From the observed microstructure, a preliminary understanding of its evolution and its relationship with the microwave dielectric properties is discussed, and some ideas to obtain truly epitaxial BST films are presented.     

Oxidation behavior of furan-resin-derived carbon alloyed with Ta or Ti

The effect of Ti, Nb and Ta on the anti-oxidation of furan-resin-derived carbons was investigated by thermogravimetric analysis combined with gas/mass spectroscopy, Hall coefficient and magnetoresistance measurements, transmission electron microscopy, and X-ray diffraction analysis. Hall coefficient and magnetoresistance measurements revealed that the electronic properties of carbons with the above metal elements, and thus their crystallinity, are similar to that of neat carbon. The oxidation rates of the carbons with a small amount of Ti or Ta are decreased up to 1000 °C compared to that of neat carbon. The number of working active sites in carbons with Ta or Ti is smaller than that in carbons with Nb or neat carbon. Ta or Ti terminates some active sites in the carbons, or somehow modifies the structures of the active sites and retards the formation of oxygen-carbon intermediate products (surface complexes) on the materials. Thus, the oxidation rate of the carbons is decreased.     

阳极氧化法制备TiO_2多孔薄膜及其光电化学性能研究

采用二步电压氧化法制备了TiO2多孔薄膜,并采用单向脉冲的电化学附载方式在制备好的TiO2多孔薄膜上进行了光敏剂5,10,15,20-四(4-羧基苯基)卟啉(TCPP)的附载。采用电化学测试法探讨了阳极氧化参数以及光敏剂TCPP的电化学附载对TiO2多孔薄膜光电化学性质的影响。结果表明,最佳的TiO2多孔薄膜阳极氧化参数为:氧化电压70~140 V,氧化θ为25℃,硫酸电解液的浓度是0.5 mol/L,氧化t为60 min。研究结果还表明,单向脉冲的电化学附载方式确实可以实现TCPP在TiO2多孔薄膜上的附载,附载后的薄膜的光电化学性能有明显提高。     

电压施加方式对阳极氧化TiO2纳米孔薄膜形貌的影响

采用阳极氧化的方法,以金属钛为基体在硫酸水溶液中于室温下制备了二氧化钛纳米孔薄膜。研究了电压施加方式对二氧化钛纳米孔薄膜的微观形貌及结构的影响。结果表明,二氧化钛纳米孔的结构与外加电压施加方式有很大关系,采用"连续加压至120-140V"方法可制备出孔径为141 nm,孔径分布最为均匀的二氧化钛纳米孔薄膜。     

Ti/Ru-Ir电极电催化氧化降解聚丙烯酰胺废水

以钛极板为阴极、钌铱电极为阳极,对聚丙烯酰胺(PAM)废水进行电催化氧化降解,探讨了电流密度、极板间距、PAM初始浓度、初始pH值等因素对PAM降解率的影响.确定最佳降解条件为:电流密度30 mA·cm-2、极板间距3 cm、初始pH值6,在此条件下,对1 L PAM初始浓度为500 mg·L-1的PAM模拟废水进行电...     

微弧氧化TiO2膜的电助光催化性能研究

以磷酸钠为电解液,采用微弧氧化技术制备钛基TiO2膜,以该膜为阳极,钛片为阴极与40 W紫外灯和稳压电源组成电助光催化体系,以大红染料模拟废水来评价TiO2膜光电催化能力。研究了酸度和亚铁离子质量浓度等因素对光催化的影响。结果表明:光电催化提高了TiO2膜阳极的降解率;阴极槽内亚铁离子存在会形成电-芬顿体系,有助于提高光电催化降解率。当电解液中支持电解质硫酸钠浓度为0.5 mol/L、pH=3时阳极槽的降解率达到38%,阴极槽亚铁离子质量浓度为3.0mg/L时降解率达到68%。     

化学溶液沉积法制备Bi4Ti3O12铁电薄膜及其性质的研究

报道了用化学溶液沉积法采用价格低廉的原料在电阻率为 6～ 9Ω·cm的 n型 Si( 1 0 0 )衬底上生长 Bi4 Ti3 O12 铁电薄膜 ,并对薄膜的性质进行了研究。结果表明此制膜工艺简单 ,成本低 ,制备的 Bi4 Ti3 O12 铁电薄膜具有较低的结晶温度 ,且薄膜均匀 ,致密 ,无裂纹。在 650°C下退火 30 min时得到的 Bi4 Ti3 O12 铁电薄膜具有良好的绝缘性和铁电性 ,薄膜的剩余极化 Pr=4.9μC/cm2 ,矫顽电场 Ec=87k V/cm     

钛硅分子筛催化丙烯环氧化过程中的副反应

钛硅分子筛(TS-1)催化丙烯环氧化过程中,H2O2能与醇溶剂发生氧化副反应。实验考察了反应物浓度、温度等因素对醇溶剂氧化的影响。结果表明反应对TS-1用量是1级,对H2O2为0到1级,对醇是0级,相同条件下3种醇的氧化程度为:异丙醇>仲丁醇>>甲醇。由提出的反应机理建立了反应动力学模型,用实验所得数据对模型进行了参数回归,结果令人满意。     

Electrocatalytic Activity of Platinum modified Polypyrrole Films for the Methanol Oxidation reaction

The catalytic activity of platinum modified polypyrrole films prepared in different ways was studied for the methanol oxidation reaction. Surprisingly, no catalytic activity was observed for films modified with colloidal platinum particles incorporated into the film during its synthesis or for the film synthesised with tetrachloroplatinate complex as a nucleophilic counter-ion, which was subsequently cathodically reduced. On the other hand, high catalytic activity was observed for platinum deposited onto pre-synthesised polypyrrole film. The platinum load, film thickness and potential of platinum deposition were found to be important parameters. High electrocatalytic activity was also observed for platinum layers deposited directly onto the glassy carbon (GC) support. However, in the latter case the stability of the electrocatalytic activity was lower when compared with the polypyrrole film modified by cathodically deposited Pt.     

敏化对微弧氧化TiO2膜光催化性能的影响

采用微弧氧化法以磷酸钠为电解液在钛片上制备TiO2膜,通过对苯胺废水的光催化降解率来表征TiO2膜的光催化性能,采用溶胶-凝胶和敏化处理对TiO2膜进行改性。实验结果表明:用溴甲酚绿敏化溶胶-凝胶法负载两次的TiO2膜,当溴甲酚绿敏化剂的质量浓度为20 mg/L,pH为5,敏化时间为16 h,TiO2膜的光催化效率达到40.6%。     

Effects of Aluminum Concentration on the Oxidation Behaviors of Reactively Sputtered TiAlN Films

Polycrystalline TiAlN films were deposited on a substrate of high-speed steel via a radio-frequency-bias reactive-sputtering process. The effects of aluminum concentration (0–60 at.%) on the high-temperature oxidation behavior of TiAlN films were explored by using in situ thermogravimetric analysis and high-temperature X-ray diffractometry. The composition and distribution of the oxidizing layers over TiAlN films were investigated. Results indicated that the oxidation resistance increased as the aluminum concentration increased. The type and location of oxidizing phases also were dependent on the aluminum concentration. Three major oxides-i.e., Al₂O₃, TiO₂, and TiO-were observed. The thickness of the Al₂O₃ layer increased and the TiO₂ gradually changed to TiO as the aluminum content increased. Thermodynamic calculations were compared to experimental observations, and they showed good agreement.