Fabrication of YBCO films on Ag substrate by TFA-MOD method

Biaxial aligned YBCO films have been successfully deposited on Ag { 110 } (110) textured polycrystalline substrates by metal-organic decomposition (MOD) method using Trifluoroacetate Salt (TFA). The influence of firing temperature and Ag surface defects on phase purity and texture, surface morphology of YBCO films was studied. Holding temperature at 900℃ for 30 rain benefits to improve orientation and connectivity of YBCO films. The surface of YBCO films deposited on unpolished Ag substrate has many holes and stripes, which are parallel to the rolling stripe on Ag substrates. To eliminate the rolling stripe on the Ag surface, Ag substrates were polished prior to films deposition. The film grown on polished Ag substrates has a smooth surface and good connectivity of grains without parallel stripes. The YBCO films have an onset of transition around 90K and critical current densities of 15000 A/cm^2.     

温度对TFA-MOD制备YBCO薄膜的影响

采用TFA-MOD方法在YSZ单晶基底上制备YBCO薄膜,主要研究高温热处理阶段温度对薄膜微结构和超导电性的影响。采用X射线衍射和扫描电镜分别对相组成与形貌进行分析。结果显示在800～830℃之间,能够获得纯的YBCO相,同时随着晶化温度的降低,薄膜面内a轴晶粒减少,有利于薄膜超导电性的改善。     

Epitaxial growth of MOCVD-derived YBCO films by modulation of Cu（tmhd）2 concentration简

Metal–organic chemical vapor deposition was applied to fabricate YBa2 Cu3 O7-d(YBCO) films on singlecrystal LaAlO3(001) substrates for its high deposition rate, easy adjustment on film composition, and low requirement on vacuum apparatus. The effects of Cu(tmhd)2 concentration in the precursor on the properties of YBCO films were systematically investigated. X-ray diffraction(XRD) reveals that the mole ratio of Cu/Ba in the precursor from 0.77 to 0.97 is helpful to improve the crystallization and out-of-plane orientation of YBCO films; however, it hardly affects the inplane texture. Scanning electron microscope(SEM) shows the dense, crack-free but rough surface, on which there are Cu–O and Ba–Cu–O outgrowths identified by energy-dispersive spectrometer(EDS). As the mole ratio of Cu/Ba increasing, the average size of Ba–Cu–O precipitates keeps increasing and the film composition becomes inhomogeneous at the mole ratio of Cu/Ba of 0.97. The 250 nm thick YBCO film prepared at the mole ratio of Cu/Ba of 0.91 shows the critical current density(Jc) of 4.0 MA cm-2(77 K, 0 T).     

Effect of solution concentration on splat formation and coating microstructure using the solution precursor plasma spray process

The Solution Precursor Plasma Spray (SPPS) process had been successfully used to deposit 7YSZ thermal barrier coatings. In this research, the effects of solution precursor concentration on 7YSZ splat formation and coating microstructure are studied. With increasing solution concentration, solution viscosity increases and surface tension decreases. Solution concentration has no effect on precursor pyrolysis and crystallization temperatures. The average atomized droplets size of ∼ 35 μm is the same for low and high concentration solutions. By contrast, splat formation is greatly dependent on precursor concentration. Low concentration precursors experience surface precipitation and lead to shell formation. The deposits consist of semi-pyrolyzed material and result in a soft, porous coating. When the substrate temperature is raised to 450 °C, spongy deposits are formed. High concentration solutions are beneficial for volume precipitation within droplets. Solid particles are formed, melted and form splats on contact with the substrate. The build-up of dense splats provides a dense coating.     

Effect of growth time on morphology and photovoltaic properties of ZnO nanowire array films

Single-crystalline ZnO nanowire arrays with different aspect ratios and nanowire densities were prepared by the hydrothermal growing method using polyethyleneimine (PEI) as a surfactant. PEI can only hinder the lateral growth of the ZnO nanowires, which is observed by high resolution transmission electron microscopy (HRTEM) analysis. Dye-sensitized solar cells were assembled by the ZnO nanowire arrays with different thicknesses, which can be controlled by the growing time and characterized using photocurrent-voltage measurements. Their photocurrent densities and energy allover conversion efficiencies increased with increasing ZnO nanowire lengths. Short-circuit current den-sity of 4.31 mA-cm-2 and allover energy conversion efficiency of 0.87% were achieved with 12.9-μm-long ZnO nanowire arrays.     

MOD法制备Zr~(4+)掺杂的YBCO薄膜及其性能

通过在前驱溶液中掺杂乙酰丙酮锆(Zr(C5H7O2)4),成功地制备了掺杂YSZ的YBCO薄膜。该YBCO薄膜具有很好的面内和面外织构,通过SEM和TEM发现,在薄膜的表面均匀地分布着大小为10nm左右的YSZ颗粒。通过对掺杂的和未掺杂的YBCO薄膜超导性能的比较发现,经过掺杂的YBCO薄膜的临界转变温度(Tc)为90.5K,比未掺杂的YBCO薄膜(Tc=91.7K)下降了1.2K;掺杂的YBCO薄膜在自场下的临界电流密度(Jc)为3.31MA/cm2,比未掺杂YBCO薄膜的Jc(3.69MA/cm2)稍微有所降低,但是在外加磁场下,掺杂的YBCO薄膜的场性能远高于未掺杂的样品,在77K,1T磁场下的掺杂样品中,其Jc值是未掺杂的YBCO薄膜的2.5倍。     

Effects of heat treatment on morphological, optical and electrical properties of ITO films by sol-gel technique

Indium-tin-oxide（ITO） films were prepared on the quarts glass by sol-gel technique. Effects of different heat treatment temperatures and cooling methods on the morphological, optical and electrical properties of ITO films were measured by TG/DTA, IR, XRD, SEM, UV-VIS spectrometer and four-probe apparatus. It is found that the crystallized ITO films exhibit a polycrystalline cubic bixbyite structure. The heat treatment process has significant effects on the morphological, optical and electrical properties of ITO films. Elevating the heat treatment temperature can perfect the crystallization process of ITO films, therefore the optical and electrical properties of ITO films are improved. But the further increasing of heat treatment temperature results in the increment of ITO films＇ resistivity. Compared with ITO films elaborated by furnace cooling, those prepared through air cooling have following characteristics as obviously decreased crystalline size, deeply declined porosity, more compact micro-morphology, improved electrical property and slightly decreased optical transmission.     

A comparative study of the properties of TiN films deposited by MAIP and FCAP

In this study two types of TiN films were prepared, one using the filtered cathodic arc plasma (FCAP) technique with an in-plane “S” filter, and the other using the multi-arc ion-plating (MAIP), and both deposited under the same parameters. Comparisons of the texture, hardness, roughness, tribological and electrochemical corrosion behaviors of the two types of TiN films were given. The TiN films obtained by the FCAP technology were found to be highly uniform, smooth and macroparticle-free. The TiN films deposited by FCAP had a (111) preferred orientation, while there was no texture in the films deposited by MAIP. Under low load the two kinds of TiN coatings had very different wear mechanisms; the films of FCAP had a lower wear rate and friction coefficient compared with the TiN films deposited by the MAIP technique. The dense and hole-free structure of TiN films of FCAP could effectively avoid the avalanche of TiN films from the substrate during corrosion tests.     

重铬酸钾对钛合金表面微等离子体氧化陶瓷膜结构和耐蚀性的影响

在钛合金表面用微等离子体氧化能产生一层陶瓷膜,将重铬酸钾引入磷酸盐电解液将使钛合金微等离子体氧化过程的槽电压升高,经对所得微等离子体氧化陶瓷膜表面和截面进行扫描电镜（SEM）形貌观察,发现重铬酸钾的加入使陶瓷膜的致密性增加,XRD分析表明,不同电解液中所得膜层都是以锐钛矿型TiO2为主晶相,同时还含有少量的金红石型TiO2,重铬酸钾的加入使锐钛矿型TiO2的含量增加,对膜层进行电偶电流和循环伏安测试表明,重铬酸钾的加入使所得的膜层对金属的接触腐蚀降低,抗点腐蚀能力大大提高。     

前驱体对四氧化三钴形貌的影响与表征

以Co(CH3COO)2.4H2O为钴源,聚乙二醇(PEG)20 000为表面活性剂,在水-正丁醇溶剂体系中,分别以氢氧化钾、碳酸铵和草酸为沉淀剂,采用沉淀法制备氢氧化钴、碱式碳酸钴和草酸钴前驱体。氢氧化钴前驱体于160℃通过水热氧化法,可制得立方体状四氧化三钴(Co3O4);碱式碳酸钴和草酸钴前驱体采用水热-热分解法分别于450℃和400℃煅烧3 h可制得球链状和棒状Co3O4。用热重分析、红外光谱、X射线衍射和透射电镜对所制得前驱体和产物Co3O4的形貌和结构进行表征,并对所制备的不同形貌Co3O4进行电化学性能测试。研究结果表明:产物Co3O4的形貌与其前驱体和制备方法有关,当采用氢氧化钴前驱体可制备平均晶粒度约为15 nm的立方体状Co3O4;当采用碱式碳酸钴和草酸钴前驱体可分别制得直径约为40 nm、长约为100 nm的球链状Co3O4和直径约为0.1μm、长度可达1μm的棒状Co3O4。通过对不同形貌的Co3O4进行循环充放电测试,可知纳米级Co3O4的电化学性能优于微米级Co3O4的;立方体状Co3O4的电化学性能优于其他形貌Co3O4的电化学性能,其循环10次后的充电比容量为406 mA.h/...     

Effect of precursor concentration on the properties of ITO thin films

Tin-doped indium oxide (ITO) thin films have been prepared by the spray pyrolysis method using indium chloride as a precursor and stannic chloride as a dopant. The effect of a precursor concentration on the structural, morphological, electrical and optical properties of films has been studied. The concentration of InCl₃ in the spraying solution is varied from 6.25 to 37.5 mM keeping doping percentage of tin fixed at its optimized value of 5 wt.%. Bare glass is used as a substrate and oxygen as the carrier and reaction gas. X-ray diffraction (XRD) patterns show that films are polycrystalline and their crystallinities are dependent on the precursor concentration. A surface morphology has been observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The typical ITO film has minimum resistivity value of 2.71 × 10⁻³ Ω cm, whose carrier concentration and mobility were 7.45 × 10¹⁹ cm⁻³ and 31 cm²/(V s), respectively. In addition, the best ITO film has optical transmittance of 94.4% and figure of merit 1.20 × 10⁻³ Ω⁻¹.     

Effects of argon gas flow rate and guide shell on oxygen concentration in Czochralski silicon growth

φ200 mm silicon single crystals were grown in the φ450 mm hot zone of a Czochralski （CZ） furnace. By modifying the pattern and the velocity of the argon flow, the silicon single crystals with different oxygen concentrations were obtained. Through numerical simulation, the velocity of the argon gas flow was plotted for the first time. The experiment resuits were analyzed and the optimum condition of the argon flow with the lowest oxygen concentration was obtained.     

Effects of la concentration on the texturing and the electrical properties of sol-gel derived PLT thin films

Lanthanum doped lead titanate (PLT) thin films consisting of different La concentrations were fabricated on Pt/Ti/SiO₂/Si using sol-gel method. The films were dried at 440°C for 5 min and fired at 600°C using rapid thermal annealing (RTA) for 1min. The preferred orientation (texturing) and the morphology of the PLT film were changed with La concentration and a possible cause of the texturing has been discussed. The effects of La doping to the Lead titanate films on the dielectric constants, P-E hysteresis loop and pyroelectric coefficient were measured and discussed.     

基片偏压对电弧离子镀ZrN薄膜微结构和表面形貌的影响(英文)

在不同的基片偏压下利用电弧离子镀技术制备氮化锆薄膜,以考察基片偏压对氮化锆薄膜微结构和表面形貌的影响。利用XRD、EPMA和FE-SEM等技术对不同偏压时得到ZrN薄膜的相结构、成分和表面形貌进行表征。结果表明,薄膜中存在立方氮化锆和六方纯锆相;随着基片偏压的增大,薄膜的择优取向由(111)变为(200),最后变为(111),晶粒尺寸由30nm减小至15nm。同时发现,随着基片偏压的增大,薄膜微结构由明显的柱状特征变为致密的等轴晶特征,表明由偏压增强的离子轰击能有效抑制柱状晶生长;薄膜沉积速率和锆氮摩尔比随着基片偏压的增大先增大后减小,在-50V时达到最大。     

Surface morphology and photoluminescence properties of ZnO thin films obtained by PLD

ZnO thin films on Si(111) substrate were deposited by laser ablation of Zn target in oxygen reactive atmosphere, Nd-YAG laser with wavelength of 1 064 nm was used as laser source. XRD and FESEM microscopy were applied to characterize the structure and surface morphology of the deposited ZnO films. The optical properties of the ZnO thin films were characterized by photoluminescence. The UV and deep level (yellow-green) light were observed from the films. The UV light is the intrinsic property and deep level light is attributed to the existence of antisite defects (Ozn). The intensity of UV and deep level light depends strongly on the surface morphology and is explained by the surface roughness of ZnO film. A strongly UV emission can be obtained from ZnO film with surface roughness in nanometer range.     

固溶-时效对Al-Zn-Mg-Sc-Zr合金板材组织与性能的影响

采用力学性能、电导率测试、金相和电子显微分析技术,研究固溶-时效处理对Al-Zn-Mg-Sc-Zr铝合金板材组织与性能的影响。结果表明:Al-Zn-Mg-Sc-Zr合金板材的最佳热处理制度为(470℃,1 h,水淬)+(120℃,24 h);在此条件下,合金的抗拉强度、屈服强度、伸长率、硬度和电导率分别为587 MPa、564 MPa、8.95%、155HB和34.5%(IACS);固溶过程中,适当提高固溶温度或延长固溶时间,合金中过剩相逐渐减少,基体过饱和程度增加;时效过程中,固溶体析出η′(MgZn2)和η(MgZn2)相,随时效时间延长,晶内析出相η′粗化,晶界上平衡相也粗化,与此同时,晶界无析出带宽化;合金的高强度来源于微量Sc、Zr引起的亚晶强化、Al3(Sc,Zr)粒子和η′相的析出强化。     

Structure and magnetic properties of columnar Fe-N thin films deposited by direct current magnetron sputtering

Columnar Fe-N thin films with thickness ranging from 30 to 150 nm were deposited by direct current magnetron sputtering using an Ar/N2 gas mixture (V(N2)/V(N2+Ar)=5%) on corning glass substrates. The structure, surface morphology and magnetic properties were investigated using X-ray diffractometry(XRD), scanning electron microscopy, atomic force microscopy, transmission electron microscopy(TEM) and superconducting quantum interference magnetometry. XRD investigation shows that Fe-N films exhibit amorphous-like structures; however, TEM measurements indicate the synthesis of mixture phases of α-Fe+ζ-Fe2N+ε-Fe3N in these films. The magnetic anisotropy and coercivity of Fe-N thin films exhibit strong dependence on the film growth behavior and surface morphology. With increasing the height of Fe-N films with column structures, the coercivity increases from 7.96 kA/m to 22.28 kA/m in the direction parallel to the film surface. In perpendicular direction the coercivity only increases slightly from 39.79 kA/m to 43.77 kA/m. However, the values of anisotropy field increase from 0.79×106 to 1.44×106 A/m, which is mainly attributed to the shape anisotropy of elongated columns due to the fact that the difference of magneto-crystalline anisotropy among these Fe-N films is small. The saturation magnetizations of Fe-N films vary with increasing film thickness from 23.5 to 85.1 A-m2/kg.     

Comparison in mechanical and tribological properties of Cr-W-N and Cr-Mo-N multilayer films deposited by DC reactive magnetron sputtering

Cr-W-N and Cr-Mo-N films were deposited on high speed steel substrate by unbalanced DC reactive magnetron sputtering. Cross-sectional scanning electron microscopy (SEM) morphologies of the films confirmed that the bilayer thickness of multilayer became thinner, and then structural transformation occurred from multilayer to composite with increasing the rotation velocity of substrate holder. X-ray diffraction (XRD) patterns indicated that the Cr-W-N films were composed of CrN and W₂N crystalline phases, and the Cr-Mo-N films consisted of crystalline CrN and amorphous/nanocrystalline Mo₂N. Mechanical and tribological properties were investigated by using a nanoindentor and a ball-on-disk tribometer, respectively. The Cr-W-N films exhibited excellent mechanical properties and wear resistance, while Cr-Mo-N films showed lower friction coefficient. Optimal mechanical and tribological properties were obtained in the Cr-W-N multilayer film with a bilayer period of 12 nm.     

醇类添加剂对冷冻浇注陶瓷的多孔结构及形貌的影响（英文）

采用冷冻浇注法制备具有层状多孔结构的氧化铝陶瓷。通过添加乙醇和正丙醇两种类型的醇类来改变水的凝固点,研究醇类的添加量及浆料的固态含量对水基氧化铝浆料的黏度、多孔陶瓷的微观结构、孔隙率和力学性能的影响。结果表明:随着浆料中乙醇和正丙醇含量的增加,浆料的黏度增加,氧化铝陶瓷的孔隙度降低;醇类的加入会使片层之间具有较好的连接从而增加多孔氧化铝陶瓷的抗压强度;当乙醇或正丙醇的添加量为30%(质量分数)时,对应的孔隙度最低,分别为68.52%和73.72%,而抗压强度最高,分别为18.2 MPa和15.0 MPa。     

分级固溶对7A04铝合金组织与性能的影响

研究了分级固溶对7A04铝合金组织与性能的影响.结果表明:7A04铝合金在470℃,5 min 485℃,· 9 min固溶和140℃,6 h 150℃,1 h时效后的бь,б0.2和δ5分别达到544.6 MPa,498.8 MPa和11.1%.金相观察发现,短时分级固溶(470℃,5 min 485℃,3～9 min)的晶粒尺寸较485℃单级固溶的细小.断口扫描电镜观察表明:分级固溶获得了典型的韧窝型断口.X射线衍射分析结果表明:470℃,5 min 485℃,9 min分级固溶后,除少量Al2Cu外,MgZn2已完全溶解.能谱分析表明:未溶相主要为富Fe和Cu的杂质相.由于470℃,5min 485℃,9 min分级固溶的晶粒比485℃单级固溶的细小,溶质过饱和度达到了500℃,20 min单级固溶的水平,使得时效后的试样获得了最高的力学性能,达到了常规固溶工艺的性能水平.