Protective Properties of High Temperature Oxide Films on Ni-based Superalloys in 3.5% NaCl Solution

The electrochemical behaviors of high temperature oxide film formed on the sputtered microcrystalline coating of M38 alloy （mc-M38） were investigated by potentiodynamic and electrochemical impedance spectroscopy （EIS） techniques in 3.5% NaCl solution. Mott-Schottky analysis was used to study the semi-conductive properties of the surface oxide. The results of the capacitance measurements showed that the oxide films on both the coating and the cast alloy were p-type semiconducting characteristics. Both the carrier density （Na）and the flat band potential （Efb） were obviously frequency-dependent, and the optimal frequency range was from 1000 to 1500 Hz. The oxidized coating exhibited higher protectivity than the oxidized cast alloy due to the lower carrier density compared with that of the oxidized cast alloy. The EIS data of the long-term immersing tests suggested that the oxide film served as an inner-barrier layer against chloride ions. The penetration of the aggressive ions into the surface oxide resulted in the decreased polarization resistance as a function of the immersion time.

An Analysis of the Influence of Protective Films on the Inner Surfaces of CCPP Headers and Steam Pipelines on Their Thermal Stress State

At present, the main attention of researchers is paid to the deterioration of heat transfer when heating the outer surface of the pipe with the liquid or steam, flowing inside it, in the presence of films or deposits on its inner surface. However, when pipe is heating by heat carrier medium, flowing inside it, film on the inner pipe surface serve a dual protective function, protecting the pipe from corrosion and reducing its thermal stress. The article represents the results of the computational analysis of protective films influence on the thermal stressed state of headers and steam pipelines of combined-cycle power plants (CCPP) heat-recovery steam generators at different transient operating conditions particularly at startups from different initial temperature states and thermal shock. It is shown that protective films have a significant influence on the stresses magnitude and damage accumulation mainly for great temperature disturbances (for thermal shock). Calculations were carried out at various thicknesses of films and assuming that their thermal conductivity less than thermal conductivity of the steam pipelines metal.

Microstructure Analysis and Properties of Anti-Reflection Thin Films for Spherical Silicon Solar Cells

Structure and properties of anti-reflection thin films of spherical silicon solar cells were investigated and discussed. Conversion efficiencies of spherical Si solar cells coated with F-doped SnO2 anti-reflection films were improved by annealing. Optical absorption and fluorescence of the solar cells increased after annealing. Lattice constants of F-doped SnO2 anti-reflection layers, which were investigated by X-ray diffraction, decreased after annealing. A mechanism of atomic diffusion of F in SnO2 was discussed. The present work indicated a guideline for spherical silicon solar cells with higher efficiencies.

Corrosion protection properties of vanadium films formed on zinc surfaces

Vanadium films were prepared on zinc surfaces by using a solution containing vanadate. Corrosion protection properties of vanadium-treated （V-treated）, chromium-treated （Cr-treated）, and untreated zinc surfaces in contact with a 3.5 wt.% NaC1 solution were studied using potentiodynamic polarization, electrochemical impedance spectroscopy （EIS）, and neutral salt spray （NSS） tests. According to these results, the V-treated layer significantly improved the corrosion resistance of zinc surfaces. In comparison with the Cr-treated layer, the V-treated layer exhibited a better corrosion resistance. The composition of the V-treated layer was studied using X-ray photoelectron spectroscopy （XPS）. XPS measurements indicated that the vanadium layer formed on zinc surfaces and the vanadium-rich coating was a hydrated oxide with a composition of V2O5, VO2, and its hydrates such as V2O5.nH2O and VO（OH）2.

Mechanism of protective film formation during CO_2 corrosion of X65 pipeline steel

Electrochemical techniques, X-ray diffraction （XRD）, and scanning electron microscopy （SEM） were applied to study the corrosion behaviors of X65 steel in static solution with carbon dioxide （CO2） at 65℃. The results show that iron carbonate （FeCO3） deposits on the steel surface as a corrosion product scale. This iron carbonate scale acts as a barrier to CO2 corrosion, and can reduce the general corrosion rate. The protection ability of the scale is closely related to the scale morphological characteristics.

Preparation of Scratch-Resistant Nano-Porous Silica Films Derived by Sol-Gel Process and Their Anti-reflective Properties

Structural strengthening of the nano porous silica films has been reported. The films were prepared with a base/acid two-step catalyzed TEOS-based sol-gel processing and dip-coating, and then baked in the mixed gas of ammonia and water vapor. The silica films were characterized with TEM, AFM, FTIR, spectrophotometer, ellipsometer, and abrasion test, respectively. The experimental results have shown that the films have a nanostructure with a low refractive index and can form an excellent scratch-resistant broadband anti-reflectance. The two-step catalysis noticeably strengthens the films, and the mixed gas treatment further improves mechanical strength of the silica network. Finally the strengthening mechanism has been discussed.

Multi-layer structures including zigzag sculptured thin films for corrosion protection of AISI 304 stainless steel

To increase corrosion resistance of the sample,its electrical impedance must be increased.Due to the fact that electrical impedance depends on elements such as electrical resistance,capacitance,and inductance,by increasing the electrical resistance,reducing the capacitance and inductance,electrical impedance and corrosion resistance can be increased.Based on the fact that these elements depend on the type of material and the geometry of the material,multilayer structures with different geometries are proposed.For this purpose,conventional multilayer thin films,multilayer thin film including zigzag structure(zigzag 1)and multilayer thin film including double zigzag structure(zigzag 2)of manganese nitride are considered to protect AISI 304 stainless steel against corrosion in salt solution.These multilayer coatings including zigzag structures are prepared by alternately using the conventional deposition of thin film and glancing angle deposition method.After deposition,the samples are placed in a furnace under nitrogen flux for nitriding.The cross sections of the structures are observed by field emission scanning electron microscopy(FESEM).Atomic force microscope(AFM)is used to make surface analyses of the samples.The results show that the multilayer thin films including zigzag structures have smaller grains than conventional multilayer thin films,and the zigzag 2 structure has the smaller grain than the other two samples,which is attributed to the effect of shadowing and porosity on the oblique angle deposition method.Crystallography structures of the samples are studied by using x-ray diffraction(XRD)pattern and the results show that nitride phase formation in zigzag 2 structure is better than that in zigzag 1 structure and conventional multilayer thin film.To investigate the corrosion resistances of the structures,electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization tests are performed.The results reveal that the multilayer thin films with zigzag structures have better corrosion protection than the conventional multilayer thin films,and the zigzag structure 2 has the smallest corrosion current and the highest corrosion resistance.The electrical impedances of the samples are investigated by simulating equivalent circuits.The high corrosion resistance of zigzag 2 structure as compared with conventional multilayer structure and zigzag 1 structure,is attributed to the high electrical impedance of the structure due to its small capacitance and high electrical resistance.Finally,the surfaces of corroded samples are observed by scanning electron microscope(SEM).

Introduction to Enhanced Protective Film Systems

An explosive blast mitigation alternative has increased the safety of structures by using " catcher" systems. These systems " catch" or repel the failure of the window or in-fill wall pro-tecting life and property from ballistic shards or fragments. They can be designed to be stand-alone in new construction and structural retrofits or used to augment structural hardening tech-niques. Cables, fabrics, and thin gauge sheet steel are examples of catcher systems used in the past. A new and evolving category of catcher systems are based on polymeric materials that can be used for both wall and window upgrades. These products are a proven blast mitigation concept and K&C Protective Technologies Pte Ltd (KCPT) together with Sherwin-Williams(SW) use KCPT′s blast engineering capacity and SW′s material engineering principles to create engineered systems for even greater in-use performance.

Review and Application Prospect of Agricultural Film for Protected Horticulture

The development of Chinese agriculture is now facing the grim situation of decreasing farmland area, increasing population and social demands, so the devel- opment of protected horticulture becomes necessary to solve the issue. This paper reviewed the characteristics of traditional horticulture films and application prospects of new functional films.

Characterization and photoelectrochemical performance of Zn-doped TiO_2 films by sol-gel method

Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.

Laser Protection with VO_2 Film

This paper presents the principle,properties,advantage and disadvantage,associated problems and trend of laser protection with VO 2 film for infrared detectors in the range of 3～5μm and 8～12μm regions and suggests VO 2 film is a potential protection material for infrared detectors.

Protective behavior of an SO_2/CO_2 gas mixture for molten AZ91D alloy

The protective behavior for a molten AZ91D alloy in an open melting furnace was investigated under a protective gas mixture containing 3% SO2 and 97% CO2, and the protection mechanism was discussed. Experimental results show that the gas mixture provides effective protection for AZ91D melt in the temperature range from 680 ℃ to 730 ℃. The microstructure, chemical composition and phase composition of the surface film formed on the molten AZ91D alloy were analyzed using scanning electron microscopy （SEM） with energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）. The SEM results demonstrate that the surface films with an average thickness between 0.5 pm and 2 pm are dense and coherent in the protected temperature range. The EDS results reveal that the surface film mainly contains elements S, C, O, AI and Mg. The XRD results show that the surface film consists of MgO, MgS and a small amount of C phase.

Microstructure and optical properties of TiO_2 thin films deposited at different oxygen flow rates

To research the influence of oxygen flow rate on the structural and optical properties of TiO2 thin film,TiO2 films on glass were deposited by reactive magnetron sputtering.The microstructure and optical properties were measured by X-ray diffractometry,AFM and UV-VIS transmittance spectroscopy,respectively.The results show that the films deposited at oxygen flow rate of 10 mL/min has the lowest roughness and the highest transmittance.The absorption angle shifts to longer wavelengths as oxygen flow rates increase from 5 to 10 mL/min,then to shorter ones as the oxygen flow rate increase from 10 to 30 mL/min.The band gap is 3.38 eV,which is nearly constant in the experiment.For the TiO2 thin films deposited at 10 mL/min of oxyge flow rate,there are nano-crystalline structures,which are suitable for anti-reflection(AR) coating in the solar cells structure system.

Electrode/Electrolyte Optimization‑Induced Double‑Layered Architecture for High‑Performance Aqueous Zinc‑(Dual)Halogen Batteries

Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.

高超声速飞行器内流道燃料超声速气膜防热/减阻协同技术研究进展

燃料超声速气膜防热/减阻协同技术是能够同时实现高超声速飞行器内流道防热和减阻的重要手段。本文首先论述了高超声速飞行器内流道面临的防热减阻需求和挑战,在此基础上进一步介绍了高超声速飞行器内流道热防护技术、高超声速飞行器内流道减阻技术、燃料超声速气膜防热/减阻协同技术的提出及基本原理,进而针对高超声速飞行器内流道燃料超声速气膜防热/减阻协同技术梳理了相关研究进展和结论。目前,相关研究已经证实了燃料超声速气膜防热和减阻协同的可行性,并且揭示了燃料超声速气膜防热减阻机理及防热/减阻协同特性,但总体而言,国内外对于燃料超声速气膜防热/减阻协同技术的研究相对较少,仍存在许多方面值得深入的探讨和研究,文章最后就未来的研究提出了几点建议。

耐暗影水性聚丙烯酸酯乳液压敏胶黏剂的制备

以丙烯酸羟乙酯(HEA)、丙烯酸(AA)、丙烯酸丁酯(BA)为反应单体,采用半连续种子乳液聚合法合成了水性聚丙烯酸酯乳液,将其进行后处理制备成乳液压敏胶黏剂。采用FTIR、TEM、TG对样品进行了表征,对其粒径、黏度进行了测试。考察了引发剂(过硫酸铵)用量(以反应单体总质量计,下同)、搅拌转速、反应温度和保温时间对聚丙烯酸酯乳液和乳液压敏胶黏剂性能的影响,探究了外加交联剂种类和用量(以聚丙烯酸酯乳液的质量计,下同)、真空处理时间对乳液压敏胶黏剂性能的影响。结果表明,引发剂用量0.4%、搅拌转速700~800 r/min、反应温度85℃、保温时间2 h条件下制备的聚丙烯酸酯乳液(PSA-1乳液)及乳液压敏胶黏剂PSA-1的各项性能较好;以氮丙啶为外加交联剂,其用量为1.0%和1.5%时,乳液压敏胶黏剂的耐暗影性能较优异;真空处理PSA-1乳液60 min时制备的乳液压敏胶黏剂PSA-1-60同时具有较优异的黏结性能及耐暗影性能,其初黏力为25#,180°剥离强度为1.85 N/cm,测试镜面板表面无可见暗影。

两种生物保护膜对瑞香红苹果果实品质的影响

【目的】研究生物保护膜对瑞香红苹果果实品质的影响,通过测定相关指标,探究瑞香红苹果免套袋栽培的可行性,为苹果免套袋生产提供技术依据与参考。【方法】以7年生瑞香红苹果为试验材料,选用两种生物保护膜康露威有机皮膜保护剂(T1)和亮金宝生物表面活性剂(T2),设置套袋(CK1)和免套袋(CK2)两个对照,测定果实外观品质和内在品质指标,调查其商品率。【结果】两种生物保护膜较套袋处理提高了瑞香红苹果单果质量、可溶性固形物质量分数、固酸比、维生素C含量、果实Ca含量、功能性营养物质含量等品质,降低了可滴定酸质量分数,提高了果实着色指数;较免套袋处理提高了商品率,降低了果锈指数、果点指数和病虫果率,提高了果面光洁指数。【结论】对不同处理的瑞香红苹果果实主要品质相关指标进行综合评价,通过隶属函数计算可知,两种生物保护膜的均值都大于0.7,都高于对照;康露威有机皮膜处理的果实品质最优,效果最好。

Quasi-in-situ Observation and SKPFM Studies on Phosphate Protective Film and Surface Micro-Galvanic Corrosion in Biological Mg-3Zn-xNd Alloys

The phosphate protective film and micro-galvanic corrosion of biological Mg-3Zn-xNd (x = 0, 0.6, 1.2) alloys were investigated by scanning and transmission electron microscopy, quasi-in-situ observation, scanning Kelvin probe force microscopy (SKPFM) and electrochemical tests. The results revealed the Mg-Zn-Nd phases formed in Mg-3Zn alloy contained with Nd. Adding Nd resulted in a significant decline in the cracks of the phosphate protective film and micro-galvanic corrosion of alloys, which were recorded by quasi-in-situ observation. In addition, the Volta potential difference of Mg-Zn-Nd/α-Mg (~ 188 mV) was lower than MgZn/α-Mg (~ 419 mV) and Zn-rich/α-Mg (~ 260 mV), and the corrosion rates of alloys markedly decreased after the addition of 0.6 wt% Nd. The improvement in corrosion resistance of Nd-containing alloys was mainly attributed to the following: (i) the addition of Nd reduced the Volta potential difference (second phases/α-Mg);(ii) the phosphate protective film containing Nd_(2)O_(3) deposited on the surface of the alloys, effectively preventing the penetration of harmful anions.

Protection behavior of SO_2 -containing cover gases to molten magnesium alloy

Sulphur dioxide （SO 2 ） mixed with carrier gases was used as an alternative to SF 6 to protect molten magnesium alloys. The protection behavior of AZ91D alloy in a sealed melting furnace was investigated under the atmosphere containing SO 2 with different mixed gases. The morphology and composition of the surface film were studied. The melt was well protected in an atmosphere of SO 2 and a proper amount of air, and was not protected properly in the other atmospheres. Based on the understanding of the protective effects of SO 2 in the sealed furnace, the protection mechanism of SO 2 -containing cover gases on molten AZ91D alloy was studied in an open melting furnace. The cover gas protected the melt by reacting with the melt to form a coherent protective film with a network structure on the melt surface. The film contains MgO and MgS. MgS increases the Pilling and Bedworth ratio of the surface film and enhances the protective capability of the films.

厚膜铂电阻输出异常分析与优化

在发动机、实验装置、仪器仪表等设备中,厚膜铂电阻用来测量与监控温度变化,若元件阻值输出异常,会使测温精度下降或无法反馈信号,甚至造成更大的经济损失。本文通过对厚膜铂电阻在装配时出现电阻值输出异常故障进行分析、观察,定位故障原因,制定防护优化措施,并进行试验验证措施有效,顺利解决了输出异常故障。