氧化钒薄膜的电学性质研究

采用离子束溅射和退火工艺,在K9玻璃基体上制备了氧化钒薄膜,并对其微观形貌及组成进行了研究.SEM结果表明,所制备的氧化钒薄膜均匀致密,晶粒尺寸达纳米量级,平均约50nm.由XPS分析可知,薄膜中钒的价态为+4价和+5价,薄膜由VO2和V2O5组成.自行研制了一套实时测量、动态显示测量结果的电阻-温度关系测试系统.应用该测试系统测量了薄膜电阻随温度变化的关系曲线,发现所制备的氧化钒薄膜具有显著的电阻突变特性,其低温段的激活能为0.3106eV,25℃时的电阻温度系数为-0.0406K-1.     

TiAl合金表面Si-Co-Y扩散渗层的高温抗氧化性能

采用扩散共渗方法在TiAl合金表面制备了Si-Co-Y渗层,分析了渗层的组织结构、形成机理及其在950 ℃时的抗氧化性能。所制备的Si-Co-Y渗层组织致密,呈多层结构：主要由TiSi₂表层,TiSi₂+Ti₅Si₄+Ti₅Si₃混合组成的外层,Ti₅Si₃中间层和TiAl₂内层组成；渗层生长过程由Si的向内扩散控制,且遵循先沉积Si后沉积Co的有序过程。氧化实验结果表明,Si-Co-Y渗层具有良好的高温抗氧化性能,在950 ℃氧化100 h后表面形成了由SiO₂, TiO₂和Al₂O₃组成的保护性氧化膜；该氧化膜的生长遵循抛物线规律,氧化增重的抛物线速率常数约为6.3×10_-2 ^mg₂^/cm₄ ^h_1/2^,较基体合金低约一个数量级。     

298 K下离子液体BMIMPF6 中电沉积制备镧金属薄膜

以无水硝酸镧、1-丁基-3-甲基咪唑六氟磷酸（BMIMPF₆）和助溶剂丙酮为电解液,在室温（298 K）下电沉积制得镧金属薄膜。电解液BMIMPF₆的电化学窗口为-2.5~1.5 V vs. Pt,La³⁺还原为La²⁺发生于-1.7 V vs. Pt,La²⁺还原为La⁰发生于-2.1 V vs. Pt。BMIMPF₆的低吸湿性有利于在空气气氛下电沉积镧。使用扫描电子显微镜和光学显微镜观察到所制备的薄膜织构致密,经能量色散谱和X射线光电子能谱对沉积薄膜进行了表征,确定了薄膜中含有大量镧元素。通过探究电压扫描速率和硝酸镧浓度对La³⁺的电化学行为的影响,证明La³⁺的还原反应是一个受物质扩散控制的不可逆过程,La³⁺在BMIMPF₆中的扩散系数为1.47×10^-9 cm²·s^-1。本研究为获得金属镧薄膜和镧氧化物薄膜提供了一种简便的方法,并且有望用于电沉积制备其它镧系元素薄膜。     

氟化钇薄膜的低温红外光学性能

采用离子束辅助电子束蒸发方法在硒化锌基底上制备氟化钇(YF₃)单层650 nm薄膜样品,基于其空间低温应用环境,利用液氮杜瓦及傅里叶变换红外光谱仪建立的薄膜材料变温光学测试系统,测试了薄膜样品在80~300 K温度条件下,在1~15 μm波长范围的光谱透射率。基于该测试结果,利用全光谱反演拟合方法对YF₃薄膜在低温下的折射率变化情况进行了研究。结果表明,YF₃薄膜折射率均随波长增大而减小,且在不同温度下变化趋势基本相同。基于Cauchy色散公式得到了YF₃薄膜在低温下的折射率与波长及温度的关系表达式,其折射率温度系数dn/dT约为6.95×10⁻⁴K⁻¹,对在任一低温下YF₃薄膜折射率快速计算提供了一个较好的方法。最后通过比较该公式得到的在300 K与80 K温度下的设计值与实际测量值的结果验证了该折射率计算表达式的准确性。     

工艺参数对低pH值2.0~2.5柠檬酸水溶液电沉积铼铱基合金薄膜特征影响

研究了在低pH值2.0~2.5的柠檬酸水溶液中恒电流电沉积富Re+Ir的Re-Ir-Ni合金薄膜特征,以及镀液温度、镀液pH、电流密度和镀液化学组成对薄膜表面形貌、化学成分和晶体结构的影响。采用环境扫描电子显微镜、X射线能谱仪和X射线衍射仪分别对合金薄膜的形貌、成分和物相进行了表征。结果表明：在电流密度为60 mA·cm^-2、pH为2.0时,获得致密光亮的Re-Ir合金薄膜。在pH=2.5时,提高镀液温度可获得质量良好的合金薄膜,而pH=2.0时,则相反。在镀液温度60~70 ℃、pH=2.0时,沉积的合金薄膜由非晶相组成;在镀液温度80 ℃时,薄膜由ReO₃相组成。在电流密度为60 mA·cm^-2、pH值从2.0增加到2.5时,合金薄膜的晶形结构由非晶态转变为晶态和非晶态的混合结构。结晶相为hcp-Ir_0.4Re_0.6和hcp-Ni。     

Ti掺杂VO2(M)粉体制备及性能研究

M相二氧化钒(VO₂(M))是一种在68℃左右具有特殊相变特性的智能隔热窗材料,然而VO₂(M)的相变稳定性还较差、对太阳光的调制能力还不够高,严重限制其在智能隔热窗中的工业化应用。本文主要以五氧化二钒为钒源,草酸为还原剂,尿素为沉淀剂,硫酸钛为掺杂剂,水热还原法制备粉体M相钛(Ti)掺杂VO₂,简称Ti-VO₂(M)粉体。通过X射线衍射仪(XRD)、场发射扫描电子显微镜(SEM)、紫外-可见-近红外分光光度计(UV-Vis-NIR)、差示扫描量热仪(DSC)和X射线能谱仪(EDS)分析所合成粉体的元素/物相组成和结构、结晶形态、太阳光反射率/透过率和相变温度的变化情况,优化Ti^₄₊掺杂量。研究发现,Ti^₄₊掺杂量控制在3%时,制备的Ti-VO₂(M)粉体的综合性能最优,为进一步应用智能隔热有机玻璃提供重要的数据与技术支撑。     

钽表面铜掺杂Ta2O5纳米棒的制备及抗菌性能研究

本实验采用两步水热法在钽基体表面制备出掺杂Cu_²⁺的Ta₂O₅纳米棒薄膜。采用XRD、SEM、XPS等方法分析了材料的物相和表面微观结构。用ICP检测了样品在生理盐水中离子析出浓度,最后通过平板计数法检验了不同含量铜掺杂Ta₂O₅薄膜的抗菌能力。结果表明,通过两步水热处理,在钽表面生成了简单斜方晶体结构的Ta₂O₅纳米棒阵列,Cu_²⁺的掺杂不会对纳米棒薄膜的微观形貌和物相造成显著影响。随时间的增加,掺铜薄膜的铜离子析出速率逐渐趋于平缓。平板计数法表明,Cu_²⁺ 的掺杂量达到2.68At%时,铜掺杂Ta₂O₅纳米棒薄膜的抗菌性能最好,抗菌率达99.2%。     

超音速大气等离子喷涂TiB2-SiC涂层的抗氧化性及耐熔盐腐蚀性能

采用超音速大气等离子喷涂制备全包覆TiB₂-SiC涂层,研究了TiB₂-SiC涂层在400和800 ℃的氧化性能,并探究其氧化机理。对TiB₂-SiC涂层在900 ℃下的抗铝熔盐腐蚀性能进行研究,并探讨其耐熔盐腐蚀机理。结果表明,超音速大气等离子喷涂制备的TiB₂-SiC涂层具有良好的抗氧化性,在400 ℃的氧化速率常数为1.92×10^-5 mg²·cm^-4·s^-1,在800 ℃的氧化速率常数为1.82×10^-4 mg²·cm^-4·s^-1。超音速大气等离子喷涂制备的TiB₂-SiC涂层在900 ℃下具有良好的抗熔盐腐蚀性能,熔盐腐蚀后TiB₂-SiC涂层都保持致密结构,未发生涂层的开裂及剥落。     

Ti6Al4V合金激光熔覆NiMoSi复合涂层的高温抗氧化性能

为提高Ti6Al4V合金的高温抗氧化性能,以Ni-48%Mo-32%Si混合粉末为原料,采用激光熔覆技术在Ti6Al4V合金表面制备复合涂层,分析涂层物相、组织结构、高温抗氧化性能及抗磨损性能,并讨论相关机理。结果表明：复合涂层中无裂纹,与基体实现了良好的冶金结合;硬质相Ti₅Si₃、MoSi₂和Mo₅Si₃均匀分布于基体α-Ti、NiTi中。经恒温800 ℃氧化100 h后,复合涂层的氧化膜主要由TiO₂、SiO₂和NiO组成,结构连续致密,表现出较好的高温抗氧化性能。而Ti6Al4V合金氧化膜主要为疏松TiO₂,表面氧化严重;氧化后,复合涂层和基体的单位面积增重分别为1.31和23.38 mg/cm²;复合涂层和基体的摩擦因数分为0.44和0.52、磨损率分别为16.2×10^-5和22.6×10^-5mm³/Nm,复合涂层的摩擦学性能亦有明显提高。     

磷-硫-钒-水体系酸性溶液中钒的提取热力学分析

针对含钒酸浸液中钒的有效提取问题，研究了298 K时磷-硫-钒-水溶液酸性体系中钒的提取热力学分析过程。结果表明，在 P(V)-V(V)-H₂O酸性溶液体系中，pH=1~4时VO₂⁺首先转变为磷钒杂多酸阴离子，pH=4~7时磷钒杂多酸阴离子转变为同多酸阴离子；在S(VI)-V(V)-H₂O酸性溶液体系中，pH=0~1时钒主要以VO₂⁺和 VO₂SO₄^-形式存在，pH=2~6时钒逐渐转变为同多酸阴离子；在P(V)-S(VI)-V(V)-H₂O酸性溶液体系中，pH=1~3 时VO₂⁺和 VO₂SO₄^-逐渐转变为磷钒杂多酸阴离子，当pΗ=2时ΣPV₁₄（所有磷钒杂多酸阴离子之和）的摩尔分数最大为88.55%；pH=4~6 时，磷钒杂多酸阴离子消失并逐渐转变为同多酸阴离子，当pΗ=5时ΣV₁₀（所有同多酸阴离子之和）的摩尔分数最大为100.00%。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。