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。     

Ti／SnO2—SbOx—PtOx氧化物电极结构和失效原因的研究

本文用 X 射线衍射,扫描电镜分析研究了 Ti/SnO_2—SbOx—P_tOx 氧化物电极的表面结构,发现 Sb 在 SnO_2中形成固溶体;Pt 能和 Sn 发生相互作用形成 PtSn 金属间化合物。电极中少量的 P_t 能使电极活性和寿命大大提高,主要有两个原因:第一.锡锑掺杂微量铂后涂层的表面积增大。第二.掺杂铂后,导电率增加。从 X 射线衍射图中还看出,Ti 基体能与活性层形成 Ti_6Sn_5金属间化合物,正是由于氧化物间形成了固溶体,界面间形成了金属化合物、使得基底与氧化物之间相互渗透,加强了基底与涂层的附着力。电极失效的原因主要是活性层的溶解和 Ti 基上 Ti 氧化物的形成。Ti 氧化物是在 Ti 基体与涂层之间,起了隔离层的作用,它使电极的导电性大大降低。SnO_2半导体近几年已经被用于电分析化学、电催化和光电化学研究中的工作电极,因为它具有高的导电率,高的机械强度,优良的耐腐蚀性,这些都符合做阳极材料的要求。因此,岩仓千秋等人近来研究了 Ti/SnO_2—SbOx—MOx(M 代表贵金属)电极在 KOH 和NaCl 溶液中的析氧和析氯的电催化活性。在过去的几年中,我们着重对 Ti/SnO_2—S_bOx—PtOx 电极在 H_2SO_4,NaCl 溶液中析氧和析氯,做为阳极材料其制作工艺、组成与它的催化活性以及使用寿命的关系进行了研究。要真正使得该电极能应用于 H_2SO_4介质中的电解及氯碱工业,弄清它的活性层结构及其作用机理是非常重要的。制得的 Ti/SnO_2—SbOx—PtOx 电极,有优良的催化活性,有希望在 NaCl 电解中取代Ru—Ti 电极。为了进一步改进 Ti/SnO_2—SbOx—PtOx 电极的性能,扩大电极的应用范围,找出电极失去活性的原因是十分必要的。国外关于 Ti/SnO_2—SbOx—PtOx 电极失效原因的报导几乎没有,只是日本的岩仓千秋等人对 Ti/SnO_2—SbOx—MOx(RuOx)电极失效的原因提出过一个假设,然而,他们并没有给予实验依据。通过实验,我们发现Ti/SnO_2—SbOx—PtOx 电极失效是一个渐变的过程。电解过程中总是伴随着表面层的溶解,直至最后 Ti 上形成了高阻性的氧化物而导致电极最终失效。     

Ni-5at.%W合金基带阳极极化行为的研究

研究了Ni-5at.%W合金基带在磷酸-硫酸及有机添加剂体系中的阳极极化行为。结合扫描电镜(SEM)、X射线光电子能谱(XPS)分析,对不同阳极极化电位区间基带表面微观形貌和相组成进行了讨论。在低电位区,电极上主要析出的是Ni(OH)2、Ni3(PO4)2及NiSO4晶体层;在高电位区,电极表面主要形成的是Ni2O3高价氧化物膜。     

退火处理对钛酸钡微弧氧化铁电薄膜物相的影响

以工业纯钛板作为阳极,在Ba(OH)2溶液中微弧氧化制得BaTiO3薄膜。研究了BaTiO3薄膜的表面形貌和物相组成,着重研究了退火处理对BaTiO3薄膜物相的影响。微弧氧化所得薄膜表面凹凸不平,且存在大量分布不均的孔洞,主要由六方相BaTiO3组成,经不同温度退火后,其物相组成发生很大变化。在1 100°C下退火1 h后,薄膜中开始出现四方相BaTiO3;随着热处理温度的升高和保温时间的延长,更多的BaTiO3由六方相向四方相转变。但高温退火过程中基体Ti与微弧氧化膜反应形成的氧化物层会影响薄膜的铁电性能。     

Fe~(3+)、Ce~(3+)掺杂SnO_2/C/Ti催化电极上苯酚的电化学行为研究

采用溶胶-凝胶法合成Fe3+、Ce3+掺杂SnO2/C胶体,通过Vulcan XC-72炭黑负载制备炭载锡系氧化物电催化剂。经X射线粉末衍射(XRD)考察了催化电极的元素组成,利用循环伏安法(CV)研究苯酚在电极上的氧化降解,考察了不同的掺杂元素、不同的掺杂量、制备工艺等因素对电极催化性能的影响。结果表明:所合成的电催化剂中的金属氧化物的主要相态为金红石型SnO2;Sn系列氧化物电极对苯酚具有一定的催化能力,适量Sb、Ce、V、Yb元素的掺杂有利于电极电化学性能的提高,Sb(2.5%)和Ce(2.5%)双掺的SnO2/C/Ti电极的氧化峰电流最大,苯酚在电极表面氧化时,均会产生一层疏松的钝化膜,苯酚仍可以穿透这层钝化膜继续在电极上氧化。     

IrO_2-SiO_2涂层钛阳极的失效行为研究

为探讨氧化物涂层阳极的失效原因,采用热分解法在不同焙烧温度下制备了60%IrO2-40%SiO2/Ti氧化物阳极,利用扫描电子显微镜(SEM)、能谱分析(EDX)和循环伏安测试(CV)分析了阳极在硫酸溶液的强化电解过程前后表面形貌、涂层组成和电化学性能的变化。结果表明,IrO2-SiO2涂层钛阳极失效的主要原因是钛基体和涂层之间形成了不导电的TiO2层。在强化电解过程中,低焙烧温度制备的阳极活性组分的电化学溶解和涂层的机械脱落促进TiO2层的生长。高焙烧温度制备的阳极中已生成一定量的TiO2,在电解时加速电极的失效。600℃焙烧温度下制备的电极的强化寿命最高。     

不同金属掺杂二氧化铅电极的对比研究

采用电沉积法制备了钛基PbO2电极和Co、Fe、La、Ce、Bi掺杂的钛基PbO2电极。利用扫描电镜、X射线荧光光谱仪、X射线衍射仪以及电化学工作站等,对比研究了不同金属掺杂PbO2电极的表面形貌、结构、电催化氧化性能和使用寿命。结果表明,Bi、Fe和Ce更容易掺杂到PbO2膜层中。Ti/PbO2–Bi和Ti/PbO2–Ce电极具有比其他电极更小的晶粒尺寸、更高的电催化氧化活性和更长的使用寿命,即Bi和Ce的掺杂能够提高Ti/PbO2电极的电催化氧化性能和使用寿命。     

换向脉冲电沉积法制备Ti/TNTs/Sb–SnO_2阳极及其性能研究

以Ti阳极氧化所得TiO_2纳米管(TNTs)为基体,采用换向脉冲电沉积制备Sb掺杂SnO_2电极(Ti/TNTs/Sb–SnO_2)。采用X射线衍射、扫描电镜、能谱等手段对其微观结构、表面形貌及元素组成进行分析,研究了它作为阳极对对硝基苯酚(p-NP)的电催化氧化降解能力。结果表明,当负向脉冲电流为60 m A时,换向脉冲电沉积法制备的Ti/TNTs/Sb–SnO_2电极的表面覆盖层均匀,致密,无裂缝。阳极极化曲线的分析结果表明,该电极的析氧电位为2.28 V,用其降解对硝基苯酚2.5 h后,去除效率达81%。     

改性钛基二氧化铅电极催化氧化降解水中四环素

使用NiO做中间层,并掺杂稀土元素(La)对Ti/PbO₂电极进行改性,制备了Ti/NiO/PbO₂-La电极。采用扫描电子显微镜、X射线能谱仪和X光电子能谱对电极表面进行表征,结果表明Ti/NiO/PbO₂-La电极表层形貌致密、规整,具有较大的活性比表面积,因此具有较Ti/PbO₂电极更多的活性位点,且La以La₂O₃的状态被掺杂在PbO₂中。通过循环伏安法(CV)、线性伏安法(LSV)和交流阻抗(EIS)一系列电化学分析,证实以NiO修饰钛基、活性层掺杂La均可以改善电极的电化学性能,且二者具有协同作用。将Ti/NiO/PbO₂-La电极用于对四环素(TC)的电催化氧化,初步分析了溶液pH、电流密度和TC初始浓度对电催化氧化反应的影响,结果表明,Ti/NiO/PbO₂-La电极对TC的电催化降解过程符合准一级动力学模型,当溶液pH为4.5,电流密度为20 mA/cm²     

cdSe_xTe_(1-x)薄膜电极光溶解性能的研究

用循环伏安法对半导体Cdse_xTe_(1-x)薄膜电池的光溶解性能进行了研究。在1mol/L KCl溶液中测量光溶解产物的阴极还原特性,考察了在多硫化钠,多硫化钾及铁氰化钾溶液中的光腐蚀行为。用此方法还研究了薄膜电极表面的光刻蚀过程和pH的影响,并用X射线光电子能谱分析光刻进行不同时间后,电极表面发生的变化。     

A mechanical and modelling study of magnetron sputtered cerium-titanium oxide film coatings on Si (100)

Ce/Ti mixed metal oxide thin films have well known optoelectrical properties amongst several other physio-chemical properties. Changes in the structural and mechanical properties of magnetron sputtered Ce/Ti oxide thin films on Si (100) wafers with different Ce:Ti ratios are investigated experimentally and by modelling. X-ray Photoemission Spectroscopy (XPS) and X-ray diffraction (XRD) confirm the primary phases as trigonal Ce₂O₃ and rutile form of TiO₂ with SiO₂ present in all prepared materials. FESEM imaging delivers information based on the variation of grain size, the mixed Ce/Ti oxides providing much smaller grain sizes in the thin film/substrate composite. Nanoindentation analysis concludes that the pure cerium oxide film has the highest hardness value (20.1?GPa), while the addition of excess titanium oxide decreases the hardness of the film coatings. High temperature in-situ XRD (up to 1000?°C) results indicate high thermal phase stability for all materials studied. The film with Ce:Ti?=?68%:32% has a new additional minor oxide phase above 800?°C. Contact angle experiments suggest that the chemical composition of the surface is insignificant affecting the water contact angle. Results show a narrow band of 87.7–95.7° contact angle. The finite element modelling (FEM) modelling of Ce/Ti thin film coatings based on Si(100); Si(110); silica and steel substrates shows a variation in stress concentration.     

Effect of the local structure of Ti-oxide species on the photocatalytic reactivity and photo-induced super-hydrophilic properties of Ti/Si and Ti/B binary oxide thin films

From the results of various spectroscopic investigations of Ti-oxide-based binary oxides, it was found that tetrahedrally coordinated Ti-oxide species are formed in the thin films of Ti/Si binary oxides with low TiO₂ content, while octahedrally coordinated TiO₂ nano-particles are formed in the Ti/B binary oxide thin films, reflecting the effect of the crystalline structures of the host SiO₂ or B₂O₃ on the local structure of the guest Ti-oxide species, respectively. The photocatalytic reactivity of the TiO₂ thin films was found to be remarkably enhanced by the dispersion of the Ti-oxide moiety into both the SiO₂ and B₂O₃ matrices, whereas the photo-induced super-hydrophilic properties of the TiO₂ thin films were enhanced only by a combination or mixing of the Ti-oxide moiety with B₂O₃.     

Fabrication of Pb(Zr,Ti)O3 thin films utilizing unconventional powder magnetron sputtering (PMS)

Pb(Zr,Ti)O3 (PZT) ferroelectric ceramic films exhibit highly superior ferroelectric, pyroelectric and piezoelectric properties which are promising for a number of applications including non-volatile random access memory devices, non-linear optics, motion and thermal sensors, tunable microwave systems and in energy harvesting (EH) use. In this research, a thin layer of PZT was deposited on two different substrates of Strontium Titanate (STO) and Strontium ruthenate (SRO) by powder magnetron sputtering (PMS) system. The preliminary powders, consisting of PbO, ZrO₂ and TiO_2, were manually mixed and placed into the target holder of the PMS. The deposition was performed at an elevated temperature reaching up to 600 °C via a ceramic heater. This high temperature is required for PZT thin film crystallinity, which is never achieved in conventional physical vapour deposition processes. The phase structure, crystallite size, stress-strain and surface morphology of deposited thin films were characterized using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The composition of the PZT thin films were also analysed by X-ray photoelectron spectroscopy (XPS). The mechanical properties of the thin films were evaluated with micro-scratch adhesive strength and micro hardness equipment. FESEM results showed that the PZT thin films were successfully deposited on both SRO and STO substrates. The surfaces of the coated samples were free from cracks, relatively smooth, uniform and dense. The profile of X-ray diffraction confirmed the formation of single-c-domain/single crystal perovskite phase grown on both substrates. The XPS analysis have shown that the PZT thin film grown by this method and that a target of PZT+10% PbO is a proper target for growing nominal PZT thin films. The adhesion strength and micro hardness results have confirmed the stability and durability of the thin film on the substrates, although higher values have been reported for thin film of PZT deposited on SRO surfaces.     

Antibacterial Thin Films on Glass Substrate by Sol–Gel Process

Antibacterial transparent thin films, containing different amounts of silver ion, have been prepared on a glass substrate by the sol–gel process. Thin films were obtained from inorganic-organic hybrid sols derived from 3-(glicydiloxypropyl)trimethoxy silane, N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane and aluminium-sec-butoxide/ethylaceto-acetate complex and doped with silver ions. The films were characterized by Scanning Electron Microscopy and Raman Spectroscopy. The physical properties of the films were studied by solar-box, taber abraser, hardness test pencil, scratch-adhesion test and spectroscopy. The antibacterial activity of the coatings were investigated against gram negative Escherichia coli and gram positive Staphylococcus aureus. The results showed that 1% doping of the transparent hybrid thin film with silver ions resulted in high antibacterial properties of the film.     

Electrochemical evaluation of molybdenum nitride electrodes in H2SO4 electrolyte

The electrochemical stability of polycrystalline thin film MoxN (x=1 and 2) electrodes deposited on previously nitrided polycrystalline Ti and bare Ti substrates and exposed to 4.4m H2SO4 electrolyte has been investigated. The electrodes were prepared by a temperature programmed procedure involving the reaction of MoO3 films and NH3. Cyclic voltammetry and a.c. impedance spectroscopy indicated that the range of electrochemical voltage stability in the electrolyte of the MoxN films on nitrided Ti substrates, referenced to a standard hydrogen electrode to be –0.01 to+0.69V. These electrodes had a calculated capacitance of about 315Fcm–3. The MoxN films on Ti substrates were electrochemically stable from –0.01 to +0.67V; however, they contained unconverted MoO2 which acted to reduce the calculated capacitance to about 210Fcm–3. At and above +0.70V and +0.68V on nitrided Ti and Ti substrates, respectively, an electrochemical reaction occurred. The formation of an amorphous phase in the reacted MoxN films was indicated by X-ray diffraction (XRD). Secondary ion mass spectroscopy (SIMS) showed increases in the atomic concentrations of hydrogen, oxygen and sulfur in the reacted films. The voltage bias applied to the electrodes influenced the chemical composition of the reacted films.     

Microstructure of Strontium Titanate Thin Film Grown by the Hydrothermal-Electrochemical Method

Microstructures of SrTiO₃ thin films grown on Ti substrates by the hydrothermal-electrochemical method have been studied by transmission electron microscopy. The grown films consisted of a thin surface layer having an isotropic polycrystalline structure and a thick inner layer having a columnar structure. Pores of the order of several tens of nanometers were found at boundaries of columnar grains constituting the inner layer. A 20- or 30-nm-thick polycrystalline layer of Ti oxides contaminated with a small amount of Sr was also found at the SrTiO₃ film/Ti substrate interface. During the film growth at this interface, the observed pores are considered to act as short-circuit paths for mass transport from the film surface to the interface.     

Impedance analysis of nanostructured iridium oxide electrocatalysts

Impedance data were collected for nanostructured iridium oxide (NIROF) at potentials below those at which the oxygen evolution reaction commences. The measurements included thin oxide films covered by a protective Nafion™ layer and thicker composite Nafion™-oxide electrodes. The time constants for the low-frequency diffusion process were approximately the same for both types of electrodes, indicating diffusion in individual particles in the porous electrode rather than across the film. The diffusion process involves trapping of the diffusion species. The impedance data indicated that there were no significant variations in conductivity of the oxides with potential, as opposed to what appears to be the case for anodically formed iridium oxide films (AIROF). This is interpreted to reflect differences in electronic structure between NIROF and AIROF.     

Adhesion at diamond-metal interfaces: a chemical composition perspective

Diamond films were chemically vapor deposited (CVD) on titanium, tungsten, molybdenum, copper and aluminum oxide substrates. In these studies, the interface formed between diamond and the substrate was exposed by mechanically deforming the metal substrate or diamond film to cause film delamination. The observed degree of adhesion for these interfaces can be ranked in the order: Ti » Al₂O₃ (thin films) > Cu > W » Mo. For highly adherent films, delamination procedures were carried out under controlled conditions in order to preserve the integrity of the interfacial species. The exposed interfaces were characterized by X-ray photoelectron spectroscopy (XPS), scanning Auger microscopy (SAM), scanning electron microscopy (SEM) and Raman microprobe spectroscopy. We find that substantial interfacial reaction layers exist at all interfaces except in the diamond-copper system and are composed of both oxides and carbides of the native substrate. Variations in the relative concentration of these species and the distribution throughout the reaction layer also were observed for the different substrates. We believe that both the chemical composition and morphology of the interface influence the adhesion properties of the diamond coating. Correlated investigations of the interfacial surfaces reveal that fracture of the diamond-metal interface occurs discretely at the diamond nucleation plane or within a reaction layer near the diamond interface. We discuss each of these findings in light of qualitative observations of adhesion and suggest avenues for improving the adhesion of diamond films.     

生长温度对单晶衬底上生长Ba(Zr_(0.2)Ti_(0.8))O_3薄膜微结构和介电性能的影响(英文)

采用脉冲激光沉积方法,在制备有LaNiO3(LNO)底电极的LaAlO3(LAO)衬底上,分别在500,600℃和700℃的沉积温度下制备了锆钛酸钡Ba(Zr0.2Ti0.8)O3(BZT)薄膜.通过X射线衍射表征薄膜的结构特性,原子力显微镜和扫描电子显微镜分别用来表征样品的表面和断面形貌.结果表明:BZT薄膜与LNO具有c轴取向,并以cube-on-cube方式排列生长.BZT薄膜表面致密无裂缝,具有柱状生长的晶粒.薄膜的介电性能测试显示:600℃下沉积的BZT薄膜具有较高的介电可调性(49.1%)和较低的介电损耗(2.5%).在600℃下沉积的BZT薄膜的优值因子(figure of merit,FOM)达到19.8.     

Fe~(3+)掺杂TiO_2薄膜材料的制备与光催化性能研究

以载玻片为基材,通过溶胶-凝胶技术制备Fe3+离子掺杂的TiO2薄膜。采用甲基橙作为目标降解物,研究Fe3+掺杂薄膜的光催化活性,采用X-射线衍射、扫描电镜和紫外-可见光吸收谱等技术对薄膜相关特征进行了表征。研究表明,当Fe/Ti物质量比为0.25%时,光催化活性最高。经500℃焙烧2h制备TiO2薄膜具有锐钛矿结构,TiO2粒子大小均匀,有孔隙结构。掺杂Fe3+使薄膜TiO2粒子减小,孔隙率增加,而粒子粒径分布不均匀增加,且吸收强度增加吸收边有一定的红移。