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原子氧与紫外综合辐照对Kapton/Al性能的影响 总被引:1,自引:0,他引:1
Kapton/Al薄膜二次表面镜是一种广泛应用的热控涂层,用于维持航天器表面正常的工作温度。本文利用激光源原子氧设备对Kapton/Al薄膜二次表面镜进行了原子氧与紫外综合辐照试验,试验前后通过高精度微量天平、扫描电镜、紫外-可见-近红外分光光度计及X射线光电子能谱仪等测试分析手段观察了材料质量损失、表面形貌、光学性能随辐照时间的演化规律,分析了试验前后Kapton/Al薄膜二次表面镜表面成份的变化。结果表明:Kapton/Al薄膜二次表面镜的质量损失随辐照时间的增加呈线性增大,原子氧与紫外综合辐照造成的质量损失明显高于单独原子氧作用产生的质量损失;试验后试样表面呈"地毯"状形貌,且随辐照时间的增加表面粗糙度变大;Kapton/Al薄膜二次表面镜的光谱反射系数随综合辐照时间的增加而降低,致使太阳吸收比的变化不断增大;试验后试样表面成份变化明显,说明原子氧和紫外环境与Kapton/Al薄膜二次表面镜表面发生了复杂的物理化学作用。 相似文献
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在模拟空间环境原子氧暴露条件下,采用激光源原子氧对热控涂层材料Kapton薄膜、Kapton/Al薄膜二次表面镜进行了不同剂量的暴露试验。研究了这两种材料的质量损失、表面形貌随原子氧暴露剂量的变化关系,以及Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率和太阳吸收比Δαs随原子氧暴露剂量的演化规律。结果表明:两种材料的质量损失随原子氧暴露剂量的增加呈线性增大;原子氧暴露后,试样表面呈"地毯"状形貌,且随暴露剂量的增加粗糙度变大;Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率随原子氧暴露剂量的增加而降低,Kapton/Al薄膜二次表面镜的太阳吸收比Δαs随暴露剂量的增加而增大。最后对Kapton薄膜的存在寿命和Kapton/Al薄膜二次表面镜绝热平面的平衡温度进行了预测。 相似文献
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为分析紫外加速老化对聚碳酸酯力学和光学性能的影响,采用实验室荧光紫外灯源暴露实验法,研究聚碳酸酯透光率、黄色指数、拉伸性能和弯曲性能随紫外辐照时间和辐照强度的变化规律.结果表明,聚碳酸酯的透光率随着辐照时间和辐照强度的增加而降低,延长辐照时间和增加辐照强度导致材料黄色指数增加.红外光谱显示,紫外加速老化使得聚碳酸酯内部生成有色基团,影响材料光学性能.聚碳酸酯的拉伸强度和断裂伸长率随着辐照时间和辐照强度的增加而降低,紫外加速老化导致材料受辐照面产生微裂纹和孔洞等缺陷,拉伸作用会使微小缺陷扩展并引发断裂.当受压面为辐照面,聚碳酸酯的弯曲强度随着辐照时间的延长和辐照强度的增加而升高,辐照面缺陷在受压状态下不易扩展并且增加了材料表面刚度,使得弯曲强度提高.聚碳酸酯的拉伸模量和弯曲模量受老化时间和辐照强度影响较小,这是因为紫外加速老化对分子量影响较小. 相似文献
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Necula BS Fratila-Apachitei LE Berkani A Apachitei I Duszczyk J 《Journal of materials science. Materials in medicine》2009,20(1):339-345
The growing fight against infections caused by bacteria poses new challenges for development of materials and medical devices with antimicrobial properties. Silver is a well known antimicrobial agent and has recently started to be used in nanoparticulate form, with the advantage of a high specific surface area and a continuous release of enough concentration of silver ions/radicals. The synthesis of MgO-Ag nanocomposite coatings by in situ deposition of silver nanoparticles during plasma electrolytic oxidation of a magnesium substrate is presented in this study. The process was performed in an electrolyte containing Ag nanoparticles under different oxidation conditions (i.e., current density, oxidizing time, silver nanoparticles concentration in the electrolyte). Surface morphology, phase composition and elemental composition (on the surface and across the thickness of MgO-Ag nanocomposite coatings) were assessed by scanning electron microscopy, X-ray diffraction, energy X-ray dispersive spectrometry and radio frequency glow discharge optical emission spectroscopy, respectively. The coatings were found to be porous, around 7 mum thick, consisting of a crystalline oxide matrix embedded with silver nanoparticles. The findings suggest that plasma electrolytic oxidation process has potential for the synthesis of MgO-Ag nanocomposite coatings. 相似文献
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Silica based sol-gel coatings doped with different silver amounts have been prepared. Apart from silver concentration, other experimental parameters such as thermal densification conditions, presence of other co-dopants and the nature of the substrate have been varied in order to determine their influence on the final microstructure and properties. Characterisation of the materials prepared was carried out by optical spectroscopy (photoluminescence and absorption), secondary ion mass spectroscopy (SIMS) and transmission electron microscopy (TEM). The study was oriented to determine the parameters governing the nucleation and growth of silver nanoparticles. The results showed that formation of silver nanoparticles was promoted when one or more of the following conditions were achieved: silver concentration in the initial sol over 5%, thermal densification under reducing atmosphere and use of pure silica substrate (in general, glass substrates without modifier ions and, therefore, with few non-bridging oxygen positions). 相似文献
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The degradation mechanism in black copper photothermal collector coatings was investigated through the use of kinetic analysis, microstructural determinations and optical modelling. The initial structure of black copper was identified using reflection electron diffraction, scanning electron microscopy and Auger electron spectroscopy sputter profiles. These results were used to develop an optical model of the as-deposited coatings. In this model, the coatings was best described as a two-layer film. The layer next to the substrate consists of dense copper oxide with metallic copper inclusions, while the rough outer layer is modelled as copper oxide dispersed in air. A substantial decrease in the solar absorptance (from 0.96 to 0.80) of coatings exposed to temperatures above 150°C in air was found to occur within 30 min and was explained by a decrease in the surface roughness of the coatings. After longer exposures, an increase in the thickness of the oxide layer near the substrate occurs at the expense of the surface layer. Incorporating this change in the model, the optical properties after thermal ageing were predicted. 相似文献
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K ZAWADZKA A KISIELEWSKA I PIWOŃSKI K KĄDZIOŁA A FELCZAK S RÓŻALSKA N WROŃSKA K LISOWSKA 《Bulletin of Materials Science》2016,39(1):57-68
Nanomaterials with high stability and efficient antibacterial activity are of considerable interest. The preparation of silver nanoparticles (AgNPs) on titania coatings and their effective antibacterial activity against Staphylococcus aureus ATCC 6538 were reported. Titanium dioxide (TiO2) coatings with AgNPs were prepared on Si wafers using the reactive magnetron sputtering method. The surface topography of AgNPs/TiO2 coatings imaged using scanning electron microscopy revealed that the size and surface density of AgNPs grown by the photoreduction of silver ions were dependent on the concentration of AgNO3 in the primary solution and the time of TiO2 exposure to UV illumination. Evaluation of the antimicrobial properties and surface analysis before and after the biological test of AgNPs/TiO2 coatings indicates their high antimicrobial stability and durability. Furthermore, the interdependence between the concentration of released silver and bacterial growth inhibition was demonstrated. In addition, direct contact killing and released silver-mediated killing have been proposed as a bactericidal mechanism of action of tested coatings with AgNPs. 相似文献
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Ali Sobhani-Nasab Mohsen Behpour 《Journal of Materials Science: Materials in Electronics》2016,27(2):1191-1196
In this research, a precipitation method was used in order to synthesize AgO nanostructures with the aid of silver nitrate as the starting reagent in an aqueous solution. To examine the effect of different surfactants such as glucose, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, and cetyltrimethylammonium bromide on the morphology and particle size of final products several tests were performed. The structural, morphological, and optical properties of as-obtained products were characterized by techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and ultraviolet–visible spectroscopy. Furthermore, the hysteresis loop measured at room temperature shows a ferromagnetic behavior of the AgO nanostructures. To evaluate the catalytic properties of nanocrystalline silver oxide (AgO), the photocatalytic degradation of rhodamine-B under visible light irradiation was carried out. 相似文献
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Martin Drábik Josef Pe?i?ka Hynek Biederman Dirk Hegemann 《Science and Technology of Advanced Materials》2015,16(2)
Nanocomposite coatings of silver particles embedded in a plasma polymer matrix possess interesting properties depending on their microstructure. The film microstructure is affected among others also by the RF power supplied during the deposition, as shown by transmission electron microscopy. The optical properties are characterized by UV–vis–NIR spectroscopy. An anomalous optical absorption peak from the Ag nanoparticles is observed and related to the microstructure of the nanocomposite films. Furthermore, a long-term aging of the coatings is studied in-depth in ambient air and in aqueous environments. It is shown that the studied films are not entirely stable. The deposition conditions and the microstructure of the films affect the processes taking place during their aging in both environments. 相似文献
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R. S. Dhabbe A. N. Kadam M. B. Suwarnkar M. R. Kokate K. M. Garadkar 《Journal of Materials Science: Materials in Electronics》2014,25(7):3179-3189
A N-doped titania–silver nanocomposites have been prepared by simple microwave assisted and impregnation–reduction method for the first time. As synthesized nanocomposites with different Ag contents were characterized for their phase purity, morphology, particle size, optical properties and elemental composition. It is found that N-doped TiO2 silver nanocomposites are pure in anatase phase with an average crystallite size of 10 nm. The catalyst was tested for dye degradation and photodegradation efficiency was found to be 99.6 and 88.7 % within 90 min under UV and sunlight respectively. A 40 % enhancement in the photodegradation efficiency was achieved by Ag loading in comparison with the N-TiO2 under sunlight. The fluorescence quenching of Ag loaded N-TiO2 indicates decrease in rate of electron–hole pair recombination that enhances photocatalytic performance. The effects of photocatalytic operational parameters such as method of surface modification, catalyst loading and irradiation sources on the photodegradation of methyl orange were also investigated. 相似文献
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Formation and thermo-assisted stabilization of luminescent silver clusters in photosensitive glasses
《Materials Research Bulletin》2013,48(4):1637-1644
Various photo-induced silver luminescent centres were obtained in photosensitive zinc and phosphate glasses containing silver ions after exposure to gamma or ultraviolet nanosecond pulsed-laser radiation. Gamma-irradiation of the glasses results mainly in the formation within the glass of electron-trapped and hole-trapped silver centres as evidenced by optical absorption, luminescence and electron spin resonance spectroscopies. For the highest irradiation doses silver clusters are obtained. Under ultraviolet nanosecond pulsed-laser exposure similar species are generated along the beam propagation direction as proven by the analogous optical and luminescence signatures. In this case for high irradiation doses few silver clusters are created. The evolution of the luminescence spectra with respect to the temperature and to the duration of the heat treatment after ultraviolet nanosecond pulsed-laser irradiation evidences the presence of potential barriers determining the stability limits of some species such as the Ag2+ hole-trapped centres or the Agmx+ clusters composed of silver ions and silver atoms. A heat treatment of several hundreds of degrees is identified as a the key parameter for tailoring the optical properties and controlling the formation of Agmx+ clusters in the photosensitive glasses. 相似文献