TiO_2微弧氧化膜的生长过程及特性变化

为了进一步研究钛材表面TiO_2微弧氧化膜的生长过程和生长模式,采用物理分析技术分析了其微弧氧化过程中不同放电阶段膜表面的形貌、膜层厚度、相成分、表面粗糙度和硬度的变化。结果表明:TiO_2多孔膜最初以孤立的岛状生长模式生长,随微弧氧化反应的进行,孤立的岛状氧化膜彼此相连接,膜表面形貌和厚度逐渐趋于一致,氧化膜的孔径、厚度、粗糙度和硬度均有增加;膜的相成分由亚稳的锐钛矿向高温下更加稳定的金红石转变,羟基磷灰石(HA)的量逐渐增加;TiO_2膜所呈现的特性与微弧氧化过程中不同阶段的放电特性密切相关。

钛表面二氧化钛膜中氧空位点缺陷传输性能的电化学研究

"钛/TiO2氧化膜/溶液"界面电极体系的电化学性能主要决定于钛表面的TiO2氧化物膜.本文利用多种电化学技术,结合半导体物理的Mott-Schottky分析和Einstein方程,研究了金属钛在1.0mol·L-1HClO4溶液中表面半导体TiO2氧化膜的生长及氧化膜中氧空位点缺陷在外加电场作用下的传输性能,并根据离子性电荷传输与电子性电荷传输对电场变化响应时间之不同特点,确定氧化膜中点缺陷扩散系数.结果表明,电极电位或阳极析氧反应对稳态电流(iss)、氧化膜的阳极化常数(α)、膜中电场强度()、以及膜中氧空位点缺陷的扩散系数(D0)等重要物理化学参数,均有显著影响,并依据氧化膜中的结构变化进行分析.

Formation Mechanistism Study of TiO2 Film Comprising Nanotubes and Nanoparticles

A novel titanium dioxide （TiO2） film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium. The local electric field at the anodized surface was simulated and its influence on the morphology of the TiO2 film was discussed. The results show that the electric field strength is enhanced by the covering. The growth rate of TiO2 increases with the assist of the local electric field. However, TiO2 dissolution is hindered since the local electric field prevents [TiF6]6- from diffusing. It means that the balance condition for the formation of nanotubes is broken, and TiO2 nanoparticles are formed. Moreover, the crystal structure of the TiO2 film was confirmed using X-ray diffraction and Raman analysis. The anatase is a main phase for the proposed film.

Fabrication of nanoporous TiO_2 films with novel surface morphology on conducting glass(FTO) substrate

The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.

高介电常数复合氧化膜低压化成箔制备及性能表征

本文使用阴极电沉积法制备高介电常数TiO_2-Al_2O_3复合低压化成氧化膜,利用LCR数字电桥、发射光谱、 SEM等测试手段对TiO_2-Al_2O_3复合低压化成氧化膜的静电容量、 Ti含量及微观形态进行了分析和表征。结果表明:钛在TiO_2-Al_2O_3复合低压化成氧化膜的表面沉积含量为3420mg/m^2。与普通阳极化成箔氧化膜相比,复合氧化膜的静电容量提升了30%以上。阴极电沉积法制备TiO_2-Al_2O_3复合低压化成氧化膜未对化成箔氧化膜形态产生影响。

Corrosion Behavior of Anodic Oxidized TiO_2 Film in Seawater

TiO2 films were formed on metallic titanium substrates by the anodic oxidation method in H2SO4 solution under the 80V D.C..Phase component and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Water contact angles on titanium oxide film surface were measured under both dark and sunlight illumination conditions.Corrosion tests were carried out in seawater under different illumination conditions by electrochemistry impedance spectrum (EIS) and polarization curves.The result showed that the TiO2 film prepared by the anodic oxidation method was anatase with a uniform structure and without obvious pores or cracks on its surface.The average water contact angle of the film was 116.4? in dark, in contrast to an angle of 42.7? under the UV illumination for 2 hours, which demonstrates good hydrophobic property.The anti-corrosion behavior of the TiO2 film was declining with the extended immersion time.Under dark conditions, however, the hydrophobic TiO2 film retarded the water infiltrating into the substrate.The impedance changed slowly and the corrosion current density was 2 orders of magnitude lower than that with the film illuminated by sunlight.All of those mentioned above indicate that the TiO2 film possesses much better performance under dark condition, and it can be applied as an engineering material under dark seawater environment.

Preparation of TiO_2-activated carbon complex membranes and their photoelectrocatalytic activity

The experimental process of preparing TiO 2 activated carbon complex membranes with activated carbon powder as main carrier, PTFE as binder and wire netting as matrix is described in detail, and both photo catalysis and photo electro catalysis are measured to study the properties of complex membranes. Experimental results show that the photo catalytic activity of the membranes is high and stable in the process of treating Rhodamine B; the application of an electric field accelerates the speed of photo catalysis, and the efficiency of photo catalysis is increased 2.5 times when the applied voltage is 0.8 V; and the degradation of Rhodamine B follows the dynamics of first order reaction. It is concluded from the discussion of experimental results that the preparation process of TiO 2 activated carbon complex membranes is a simple low cost process suitable for large scale application.

Synthesis of Three-Dimensional Agaric-like Biomorphic TiO_2 by a Facile Method with Coscinodiscus sp.Frustule

The paper aims to expand the application of natural marine algae. Marine diatoms, which have intricate frustule struc- tures, can serve as bio-template for preparing three-dimensional materials. A simple and effective approach to synthesize the corru- gated agaric-like biomorphic TiO2 templated with frustule of Coscinodiscus sp. is reported. In the sol-gel preparation process, the titania-coating on the frustule is prepared through the deposition and condensation with the aid of acetylacetone （acac） as a control- ling agent to make the precursor Ti（BuO）4 hydrolyze slowly. The as-prepared titania-coated frustule and biomorphic TiOz is charac- terized by scanning electron microscopy （SEM） attached with energy dispersive X-ray spectrometer （EMAX） and X-ray diffraction （XRD）. The microstructure of the corresponding titania nanoparticles appears to be sphere with the diameters distributed around 10-20nm. The templating process is repeated for three cycles. Subsequently, the three-dimensional freestanding corrugated aga- ric-like biomorphic TiO2 structure is obtained by a selective removal in the NaOH solution. As far as we known, the 3D freestanding corrugated agaric-like biomorphic TiOz with greatly increased surface area is obtained for the first time.

Hybrid functional IrO_2-TiO_2 thin film resistor prepared by atomic layer deposition for thermal inkjet printheads

IrO2-TiO2 thin films were prepared by atomic layer deposition using Ir（EtCp）（COD） and titanium isopropoxide （TTIP）. The resistivity of IrO2-TiO2 thin films can be easily controlled from 1 500 to 356.7 μΩ·cm by the IrO2 intermixing ratio from 0.55 to 0.78 in the IrO2-TiO2 thin films. The low temperature coefficient of resistance（TCR） values can be obtained by adopting IrO2-TiO2 composite thin films. Moreover, the change in the resistivity of IrO2-TiO2 thin films was below 10% even after O2 annealing process at 600 ℃. The step stress test results show that IrO2-TiO2 films have better characteristics than conventional TaN08 heater resistor. Therefore, IrO2-TiO2 composite thin films can be used as a heater resistor material in thermal inkjet printhead.

Self-Organizing Evolution of Anodized Oxide Films on Ti-25Nb-3Mo-2Sn-3Zr Alloy and Hydrophilicity

In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased electrolyte containing 0.5wt% NH4F.The nanostructured TiO2 films exhibited three distinct types depending on the anodization time:top irregular nanopores(INP)/beneath regular nanopores(RNP),top INP/middle regular nanotubes(RNT)/bottom RNP and top RNT with underlying RNP.The evolution of the nanostructured TiO2 films with anodization time demonstrated that self-organizing nanopores formed at the very beginning and individual nanotubes originated from underlying nanopore dissolution.Furthermore,a modified two-stage self-organizing mechanism was introduced to illustrate the growth of the nanostructured TiO2 films.Compared with TLM titanium alloy matrix,the TiO2 films with special nano-structure hold better hydrophilicity and higher specific surface area,which lays the foundation for their biomedical applications.

阳极氧化法制备TiO_2膜在模拟深海热液区的耐腐蚀性能

以恒压阳极氧化方法在钛基体上制备TiO_2氧化膜,使用水热釜模拟深海热液区的条件研究其耐腐蚀性能。采用XRD、SEM、接触角测定仪对氧化膜以及腐蚀试样产物进行晶型、表面结构、化学成分和亲疏水性能测定,使用动电位扫描方法对其进行极化曲线测试。结果表明,钛试样和阳极氧化钛试样在模拟深海环境条件下,经过腐蚀反应在表面都生成了一层非致密的TiO_2膜,对基体并不能起到保护作用,而阳极氧化生成的致密TiO_2膜对基体能够起到很好的保护作用。经腐蚀后钛试样表面有TiH_2相的形成,腐蚀电位负移0.45 V。而阳极氧化钛试样表面没有TiH_2相的形成,且腐蚀电位负移较小,表现出良好的耐腐蚀性能。

Preparation of defect free ceramic/Ti composite membranes by surface modification and in situ oxidation

Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.

Formation and capacitance properties of Ti-Al composite oxide film on aluminum

Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.

添加纳米Al微微粒对纯钛微弧氧化膜层性能的影响

在微弧氧化电解液中添加纳米Al微粒,在纯钛表面进行微弧氧化制备Al2O3/TiO2复合微弧氧化膜,采用Quant 200型扫描电子显微镜(SEM)观察膜层的表面形貌,并研究纳米Al微粒对微弧氧化复合膜层硬度和耐磨性能的影响。结果表明,纳米Al微粒的添加可使纯钛微弧氧化膜的表面更加平整致密,硬度和耐磨性显著提高。电解液中添加3 g/L纳米Al微粒后,微弧氧化的终止电压由460 V上升至515 V,硬度由811 HV提高至1232 HV,平均摩擦系数由0.68降低至0.57,磨损失重由1.0 mg降低至0.58 mg。

A multijunction of ZnIn2S4 nanosheet/TiO2 film/Si nanowire for significant performance enhancement of water splitting

Photoelectrodes with a specific structure and composition have been proposed for improving the efficiency of solar water splitting. Here, a novel multijunction structure was fabricated, with Si nanowires as cores, ZnIn2S4 nanosheets as branches, and TiO2 films as sandwiched layers. This junction exhibited a superior photoelectrochemical performance with a maximum photoconversion efficiency of 0.51%, which is 795 and 64 times higher than that of a bare Si wafer and nanowires, respectively. The large enhancement was attributed to the effective electron-hole separation and fast excited carrier transport within the multijunctions resulting from their favorable energy band alignments with water redox potentials, and to the enlarged contact area for facilitating the electron transfer at the multijunction/electrolyte interface.

Formaldehyde gas sensor based on TiO_2 thin membrane integrated with nano silicon structure

An innovative formaldehyde gas sensor based on thin membrane type metal oxide of Ti O2 layer was designed and fabricated. This sensor under ultraviolet(UV) light emitting diode(LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m^3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system(MEMS) processing technology. First, plasma immersion ion implantation(PIII) was adopted to form black polysilicon, then a nanoscale TiO_2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.

Electron transport in dye-sensitized solar cells based on TiO_2 nanowires

Anatase titanium dioxide nanowire arrays were prepared by hydrothermally oxidizing titanium foils in aqueous alkali and transferred onto fluorinated tin oxide(FTO)glass for use as the photoanodes of front side illuminated dye-sensitized solar cells(DSCs).Electrochemical impedance spectroscopy(EIS)measurement was applied to compare the electron transport and recombination properties of DSCs using TiO2nanowire films and TiO2nanoparticle films as photoanodes.It was found that the nanowire array films possess smaller electron transport resistance(Rt)and larger electron diffusion length(Le)in the photoanodes,suggesting that the nanowire arrays can enhance the electron transport rate and have a potential to improve the charge collection efficiency of DSCs.

自洁玻璃的开发应用与市场

本文对自洁玻璃的生产及品种进行了介绍，并介绍了国内国外自洁玻璃的发展动态，同时对市场需求做了预测。

体育器材用纯钛组织材料耐腐蚀性分析

纯钛组织材料较强的耐腐蚀性可以延长体育器材的使用寿命,但是热氧化温度和时间会影响纯钛组织材料耐腐蚀性能,提出了体育器材用纯钛组织材料耐腐蚀性分析研究。选取工业纯钛焊接钛板为实验对象,采用不锈钢丝刷清理工业纯钛焊接钛板的表面氧化部分,在箱式电阻炉中经过热氧化处理后,分析了纯钛试样在盐酸溶液和过氧化氢溶液中的耐腐蚀性能,采用扫描电镜,分析纯钛试样氧化层表面的形貌,结合纯钛试样表层的相组织,利用电子天平称纯钛试样的重量。结果表明,纯钛试样在600℃的热氧化温度下,表面就会形成一层TiO_(2)氧化膜,TiO_(2)氧化膜的厚度会随着温度的升高而逐渐增大,改善了纯钛试样在28%~34%盐酸和20%过氧化氢中的耐腐蚀性能,最终确定提高体育器材用纯钛组织材料耐腐蚀性能的最佳温度和时间为700℃和300~500min。