复配气相缓蚀剂对多种金属大气腐蚀的综合保护作用研究

为了应对海洋大气环境中电子设备容易被腐蚀的难题,制备了一种复配气相缓蚀剂。通过半封闭空间挥发减量试验、缓蚀膜疏水性表征、模拟环境和海洋大气环境试验等评价了复配气相缓蚀剂对钢、T2紫铜、黄铜、银、铝等电子设备常用金属的气相缓蚀性能。结果表明:复配气相缓蚀剂对以上金属均具有显著的缓蚀作用,其中对钢的缓蚀率为86.9%,对T2紫铜为58.7%,对黄铜为96.2%,对银和铝在模拟腐蚀环境中具有一级气相缓蚀能力,是一种性能优良的电子设备多金属大气腐蚀综合防护材料。     

沉积扩散法制备含银抗菌不锈钢工艺研究

采用沉积扩散法制备含银抗菌不锈钢层,通过抗菌试验、盐干湿循环腐蚀试验、SEM、XPS等检测手段,研究了沉积扩散工艺制备含银抗菌不锈钢的抗菌性能、耐蚀性能及银在不锈钢基体中的分布状态和价态.结果表明,基材表面化学镀银后经离子轰击抗菌处理(工艺参数:电压1.25 kV,电流3 A,气流量20～60 mL/min,时间4 h),所得含银抗菌不锈钢的杀菌率达到99%以上,耐蚀性能没有降低,银在基体中呈弥散状态分布,其价态为零价态.     

Hydroxyapatite microparticles as feedback-active reservoirs of corrosion inhibitors

This work contributes to the development of new feedback-active anticorrosion systems. Inhibitor-doped hydroxyapatite microparticles (HAP) are used as reservoirs, storing corrosion inhibitor to be released on demand. Release of the entrapped inhibitor is triggered by redox reactions associated with the corrosion process. HAP were used as reservoirs for several inhibiting species: cerium(III), lanthanum(III), salicylaldoxime, and 8-hydroxyquinoline. These species are effective corrosion inhibitors for a 2024 aluminum alloy (AA2024), used here as a model metallic substrate. Dissolution of the microparticles and release of the inhibitor are triggered by local acidification resulting from the anodic half-reaction during corrosion of AA2024. Calculated values and experimentally measured local acidification over the aluminum anode (down to pH = 3.65) are presented. The anticorrosion properties of inhibitor-doped HAP were assessed using electrochemical impedance spectroscopy. The microparticles impregnated with the corrosion inhibitors were introduced into a hybrid silica-zirconia sol-gel film, acting as a thin protective coating for AA2024, an alloy used for aeronautical applications. The protective properties of the sol-gel films were improved by the addition of HAP, proving their applicability as submicrometer-sized reservoirs of corrosion inhibitors for active anticorrosion coatings.     

海洋环境下热喷涂锌、铝及其合金涂层防腐蚀机理研究概况

综述了国内外几十年来在不同海水环境中对热喷涂锌铝及其合金涂层防护性能和机理研究的成果.热喷涂锌铝及其合金涂层在海洋环境中具有优良的长效防护性能,锌具有优良的电化学保护性,铝具有比锌更好的化学稳定性,锌铝合金既保留了锌的电化学特点,又具有铝的化学稳定性能.指出了今后的研究重点应该是金属与有机复合层在浪花飞溅区苛刻腐蚀环境下界面的腐蚀规律和腐蚀机理的探讨,对金属与有机复合层界面的腐蚀原因在理论上做出了本质的解释,并能预测涂层体系的防腐蚀寿命.     

Corrosion Resistance of Graphene-Reinforced Waterborne Epoxy Coatings

Graphene(G) was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings.The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated.The composite coatings displayed outstanding barrier properties against H_2O molecule compared to the neat epoxy coating.Open circuit potential(OCP),Tafel and electrochemical impedance spectroscopy(EIS)analysis con-?rmed that the corrosion rate exhibited by composite coatings with 0.5 wt%G was an order of magnitude lower than that of neat epoxy coating.Salt spray test results revealed superior corrosion resistance offered by the composite coating.     

Acoustic vibrations of metal-dielectric core-shell nanoparticles

The acoustic vibrations of metal nanoparticles encapsulated in a dielectric shell (Ag@SiO(2)) were investigated using a time-resolved femtosecond technique. The measured vibration periods significantly differ from those predicted for the bare metal cores and, depending on the relative core and shell sizes, were found to be either larger or smaller than them. These results show that the vibration of the whole core-shell particle is excited and detected. Moreover, vibrational periods are in excellent agreement with the predictions of a model based on continuum thermoelasticity. However, such agreement is obtained only if a good mechanical contact of the metal and dielectric parts of the core-shell particle is assumed, providing a unique way to probe this contact in multimaterial or hybrid nano-objects.     

全光亮化学镀镍磷合金工艺研究

研究出了一种新型不含铅的全光亮化学镀镍工艺,获得了全光亮的镍磷合金镀层.通过试验分析镀液中添加剂、无机盐、主盐、施镀时间、pH值和施镀温度对化学镀镍磷合金层光亮度的影响;检测了有关性能.结果表明:所得化学镀镍磷合金镀层的光亮度、耐蚀性等性能优于常规化学镀镍磷合金镀层.CuSO4、TaSO4无机盐的添加使溶液稳定性(氯化钯稳定试验)从30 s提高到90 s,同时也提高了化学镀镍磷合金镀层耐蚀性,在5%NaCl溶液中的年腐蚀量从1.1 mg/cm2降为0.     

Ni-Cu-P化学镀层的制备及其耐烟气冷凝液的腐蚀性能

为了解决冷凝式燃气利用设备的腐蚀问题,采用化学镀工艺在紫铜基体上沉积Ni-Cu-P层.利用扫描电镜(SEM)、电子能谱(EDX)、电子探针(EPMA)分析镀层的形貌和成分,利用极化曲线和交流阻抗谱考察了紫铜基材及其Ni-Cu-P镀层在15℃和60℃煤气烟气冷凝液中的耐腐蚀性能.结果表明:Ni-Cu-P化学镀层表面均匀平...     

Vancomycin-functionalised Ag@TiO2 phototoxicity for bacteria

This study reports on the synthesis of vancomycin (Van)-functionalised Ag@TiO(2) nanoparticles and their enhanced bactericidal activities. Van-Ag@TiO(2) nanoparticles were prepared by nanoparticle deposition and chemical cross-linking reactions. The catalysts showed high efficiency for the degradation of methylene blue under ultraviolet (UV) illumination. The photocatalytic inactivation of the sulphate-reducing bacteria, Desulfotomaculum, was also studied under UV light irradiation and in the dark using aqueous mixtures of Ag, Ag@SiO(2), Ag@TiO(2), and Van-Ag@TiO(2). The Van-Ag@TiO(2) nanoparticles showed a capacity to target Van-sensitive bacteria. They also effectively prevented bacterial cell growth through the functionalised nanoparticles under UV irradiation for 1h. To investigate the specificity of the catalyst phototoxicity, a Van-resistant bacteria, Vibrio anguillarum, was used as the negative control. The results indicated that Van-Ag@TiO(2) nanoparticles had a higher selective phototoxicity for Van-sensitive bacteria. Therefore, the antibiotic molecule-functionalised core-shell nanoparticles allow for selective photokilling of pathogenic bacteria.     

水电站大坝金属结构物的防腐蚀措施及效果

水电站金属结构物受到大气、水、泥沙的腐蚀破坏,必须对其进行周期性检修和防腐蚀保护.以三峡 -葛洲坝水利枢纽实践为基础,介绍了水电站金属结构物防腐蚀保护方法以及金属层、有机涂料、无机涂料等防腐蚀材料的选用.在高速水流区金属结构物采用环氧金刚砂涂层、热喷碳化钨涂层及钛纳米聚合物涂层,水下金属结构物采用热喷锌层加有机涂料层封闭,大气环境下金属结构物采用环氧类涂料作底涂和丙烯酸聚氨酯涂料作面涂,都取得了比较好的防腐蚀效果.     

Corrosion protection investigation of reinforcement by inorganic coating in the presence of alkanolamine-based inhibitor

Corrosion of reinforced concrete structures is a major problem throughout the world, demanding significant amounts for repair and rehabilitation. Corrosion protection is commonly performed by coating the concrete or by using corrosion inhibitors. This paper describes the comparative evaluation of the effectiveness of an acrylic dispersion and an inorganic coating on silicate basis, of an alkanolamine-based corrosion inhibitor and of their combination, on reinforced mortar specimens partially immersed in 3.5% NaCl solution. The following techniques were used: strain gauges, measurements of the corrosion potential, the mass loss and the EIS of the reinforcing bars and measurements of the chloride diffusion and the carbonation depth in mortars. Results demonstrate that the simultaneous use of the alkanolamine-based corrosion inhibitor with the inorganic coating offers a protection degree comparable to that of the acrylic dispersion, which performs best in the presence of both chloride ions and carbon dioxide.     

纳米TiO2浆料改性氯醚树脂防蚀涂层的初步研究

氯醚树脂生产环保、防蚀性能好,但其耐候性不佳,有待改进.纳米TiO2抗紫外性能优异,但有关其改性防蚀涂料及性能的研究鲜见报道.为此,采用金红石型纳米TiO2对氯醚树脂防蚀涂料进行了改性处理,并用国家标准和人工加速老化试验考察了纳米TiO2的加入对氯醚树脂涂层的附着力、柔韧性、耐冲击、紫外老化等性能的影响,用电化学阻抗法考察了添加纳米TiO2对漆膜防蚀性能的影响.结果表明,添加纳米TiO2对氯醚树脂漆膜的附着力、柔韧性和耐冲击没有明显改善,但能提高漆膜耐紫外老化的性能,漆膜的光泽度也有所提高,纳米TiO2加入适量时还能提高漆膜的防蚀性能.因此,纳米材料在氯醚树脂防蚀涂料中的应用是可行的.     

长效防腐蚀涂层体系热带海水环境中22年的腐蚀行为

钢结构在海洋环境中腐蚀严重,为了提供好的防护体系,对金属热喷涂涂层(Zn、Al、Al-Me-Re和Zn-Al)经封闭涂装处理的复合防护体系和以无机富锌为底涂层的重防腐蚀体系,在榆林海水环境下进行连续22 a的长期曝露试验.结果表明:在全浸、潮差和飞溅区,Zn+聚氨酯有机涂层防腐蚀体系在海洋环境中的防腐蚀寿命小于4 a;Al+有机涂层体系、Zn-Al+有机涂层体系和Al-Me-Re+有机涂层体系的防腐蚀寿命大于16 a,尤其在榆林全浸区防腐蚀寿命大于22 a;无机富锌+8401有机涂层体系,在全浸、潮差和飞溅区防腐蚀寿命可达16 a.说明Al+有机涂层、Zn-Al+有机涂层和Al-Me-Re+有机涂层体系在海洋环境中具有优异的防腐蚀性能.     

Fabrication of antibacterial monodispersed Ag-SiO2 core-shell nanoparticles with high concentration

Monodispersed Ag-SiO₂ core-shell nanoparticles with a high concentration of 400 mg/L were successfully fabricated by using tetraethoxysilane as silica precursor and reducing silver nitrate with ascorbic acid in the presence of cetyltrimethylammonium bromide as stabilizing agent. The nanoparticles had a spherical silver core in a size range from 14-26 nm in diameter and an amorphous silica shell of 15-28 nm thickness, respectively. The antibacterial effects of Ag-SiO₂ core-shell particles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were tested by the usual twofold serial dilution method for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The results indicated that the core-shell nanoparticles owned excellent antibacterial effects.     

Core and shell sizing of small silver-coated nanospheres by optical extinction spectroscopy

Silver metal nanoparticles (Nps) are extensively used in different areas of research and technology due to their interesting optical, thermal and electric properties, especially for bare core and core-shell nanostructures with sizes smaller than 10?nm. Since these properties are core-shell size-dependent, size measurement is important in manipulating their potential functionalization and applications. Bare and coated small silver Nps fabricated by physical and chemical methods present specific characteristics in their extinction spectra that are potentially useful for sizing purposes. This work presents a novel procedure to size mean core radius smaller than 10?nm and mean shell thickness of silver core-shell Nps based on a comparative study of the characteristics in their optical extinction spectra in different media as a function of core radii, shell thickness and coating refractive index. From the regularities derived from these relationships, it can be concluded that plasmon full width at half-maximum (FWHM) is sensitive to core size but not to coating thickness, while plasmon resonance wavelength (PRW) is related to shell thickness and mostly independent of core radius. These facts, which allow sizing simultaneously both mean core radius and shell thickness, can also be used to size bare silver Nps as a special case of core-shell Nps with zero shell thickness. The proposed method was applied to size experimental samples and the results show good agreement with conventional TEM microscopy.     

用电化学方法研究火焰喷涂乙烯丙烯酸共聚物涂层的防腐蚀性能

为了研究乙烯丙烯酸共聚物(EAA)涂层的防腐蚀性能,采用火焰喷涂技术制备了EAA涂层,利用傅里叶变换红外光谱(FTIR)研究了火焰喷涂对EAA涂层结构的影响;用扫描电镜(SEM)和拉伸强度试验研究了EAA涂层的形貌及力学性能;利用交流阻抗(EIS)和Tafel曲线研究了EAA涂层在3.5%NaCl溶液中的防腐蚀性能,初步探讨了其机理。结果表明:EAA涂层结构密实,与基体结合良好,其在3.5%NaCl溶液中浸泡初期能起到良好的腐蚀屏蔽作用,随着浸泡时间的延长,腐蚀介质通过涂层的通孔、微裂纹等缺陷渗入涂层与基体的界面腐蚀基体,使涂层电阻Rc下降、电容Cc增加、腐蚀电位Ecorr负移、腐蚀电流密度Jcorr增加,涂层防腐蚀性能减弱。     

Effects of Nano Pigments on the Corrosion Resistance of Alkyd Coating

Alkyd coatings embedded with nano-TiO2 and nano-ZnO pigments were prepared. The effects of nano pigments on anticorrosion performance of alkyd coatings were investigated using electrochemical impedance spectrum （EIS）. For the sake of comparison, the corrosion protection of alkyd coatings with conventional TiO2 and ZnO was also studied. It was found that nano-TiO2 pigment improved the corrosion resistance as well as the hardness of alkyd coatings. The optimal amount of nano-TiO2 in a colored coating for corrosion resistance was 1%. The viscosities of alkyd coatings with nanometer TiO2 and ZnO and conventional TiO2 and ZnO pigments were measured and the relation between viscosity and anticorrosion performance was discussed.     

Nanoparticles-based phenol-formaldehyde hybrid resins

The synthesis, characterization and corrosion properties of a novel material, produced by the reaction of silica nanoparticles with a functionalized Phenol-Formaldehyde Resin (PFR), are presented. Carboxylic groups were attached in situ to the PFR skeleton to produce a functionalized resin (PFR-SA), which is then reacted with sol-gel-prepared silica nanoparticles, yielding a novel hybrid (organic/inorganic) material (PFR-SA-nanoSiO2). This hybrid material was characterized by FT-IR, FT-Raman, TGA, DSC, SEM and corrosion tests, whose results showed significant improvement of the thermal properties in comparison with the PFR coating. In addition, the new material was efficient and durable against corrosion of metals, with the anticorrosive performance of PFR-SA and PFR-SA/nanoSiO2 coating films being superior to those of the original PFR coating.     

Antimicrobial active silver nanoparticles and silver/polystyrene core-shell nanoparticles prepared in room-temperature ionic liquid

Uniform silver nanoparticles and silver/polystyrene core-shell nanoparticles were successfully synthesized in a room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]·BF₄). [BMIM]·BF₄ plays a protective role to prevent the nanoparticles from aggregation during the preparation process. Transmission electron micrographs confirm that both silver nanoparticles and core-shell nanoparticles are regular spheres with the sizes in the range of 5–15 nm and 15–25 nm, respectively. The X-ray diffraction analysis reveals the face-centered cubic geometry of silver nanoparticles. The as-prepared nanoparticles were also characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. In addition, antimicrobial activities against E. coli and S. aureus were studied and the results show that both silver nanoparticles and core-shell nanoparticles possess excellent antimicrobial activities. The antimicrobial mechanism of the as-prepared nanoparticles was discussed.     

Gram-scale synthesis and biofunctionalization of silica-coated silver nanoparticles for fast colorimetric DNA detection

A direct silica-coating method has been developed for the gram-scale synthesis of well-dispersed Ag@SiO(2) nanoparticles. Subsequent surface functionalization via the well-established silica surface chemistry provided arching points for straightforward bioconjugation with amino-terminated oligonucleotides. Fast hybridization kinetics of the resulting robust oligo-modified Ag@SiO(2) nanoprobes with complementary target oligonucleotides render themselves very useful for the fast colorimetric DNA detection based on the sequence-specific hybridization properties of DNA. Additionally, the reliable protocols developed in this study for preparing and functionalizing Ag@SiO(2) nanoparticles can be readily extended to other silica-coated nanoparticles, which can also provide a specific platform for the covalent attachment of biomolecules such as amino-rich proteins, enzymes, or amino-terminated oligonucleotides for diverse bioapplications.