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1.
The infrared emissivity of low emissivity coating can be significantly reduced by adding high content concentrations of parallel distributed metallic flake pigment. However, the infrared emissivity is very difficult to calculate by the existing theory models, such as the light scattering theory and traditional Kubelka-Munk radiative transfer model, because of shape and distribution anisotropy of flake pigments. Thus, the low emissivity coating is assumed to be the superposition structure of homogeneous layers and metallic flakes are approximately uniform and parallel arrangement in each layer. Based on geometric optics theory and Kubelka's layer model, considering multiple reflection, transmission and absorption of infrared radiation among different layers, the theoretical model is established to calculate the coating emissivity. The facts of binder, pigment concentration and thickness are also systematic discussed. The result shows that the law of influence on infrared emissivity can be correctly simulated by this theoretical model. Transparent binder, high volume concentration of thin flake pigment can facilitate to reduce infrared emissivity. Moreover, this model offers the possibility of predicting the infrared optical properties of coatings by their optical constants. 相似文献
2.
The epoxy-siloxane/Al composite coatings with low infrared emissivity for high temperature applications 总被引:1,自引:0,他引:1
Chen Hu Guoyue Xu Xingmei Shen Chunming Shao Xiaoxing Yan 《Applied Surface Science》2010,256(11):3459-3463
Low infrared emissivity coatings with good thermal resistance were prepared by using epoxy-siloxane and aluminum as adhesive and pigment, respectively. The influence of chemical composition, surface texture, roughness and thickness on the infrared emissivity was systematically investigated. The detailed results of experimental investigation indicate that the cured composite coatings could possess low emissivity value. Due to reducing infrared absorption and forming uniform and compact char construction, the infrared emissivity decreases obviously. Both the surface roughness and thickness have a critical value, respectively. Too large roughness or thickness would not contribute to the decrease of the emissivity. Moreover, the composite coatings were tested for thermal stability in air to explore the effect of high-temperature environment on the emissivity. The results indicate that the composite coatings, still possessing low emissivity after the test, exhibit favorable thermal ageing and thermal shock resistance. 相似文献
3.
Comparison of anti-corrosion properties of polyurethane based composite coatings with low infrared emissivity 总被引:1,自引:0,他引:1
Yajun Wang Guoyue XuHuijuan Yu Chen HuXiaoxing Yan Tengchao GuoJiufen Li 《Applied Surface Science》2011,257(10):4743-4748
Four polyurethane resins, pure polyurethane (PU), epoxy modified polyurethane (EPU), fluorinated polyurethane (FPU) and epoxy modified fluorinated polyurethane (EFPU), with similar polyurethane backbone structure but different grafting group were used as organic adhesive for preparing low infrared emissivity coatings with an extremely low emissivity near 0.10 at 8-14 μm, respectively. By using these four resins, the effect of different resin matrics on the corrosion protection of the low infrared emissivity coatings was investigated in detail by using neutral salt spray test, SEM and FTIR. It was found that the emissivity of the coatings with different resin matrics changes significantly in corrosion media. And the results indicated that the coating using EFPU as organic adhesive exhibited excellent corrosion resistance property which was mainly attributed to the presence of epoxy group and atomic fluorine in binder simultaneously. 相似文献
4.
Low infrared emissivity of polyurethane/Cu composite coatings 总被引:5,自引:0,他引:5
Huijuan Yu Guoyue Xu Xingmei Shen Xiaoxing Yan Chuangwei Cheng 《Applied Surface Science》2009,255(12):6077-6081
Polyurethane/Cu composite coatings with low infrared emissivity near to 0.10 at the wavelength of 8-14 μm were prepared by a simple and convenient process. The influences of the content of Cu powder, surface roughness, coating thickness and temperature on infrared emissivity of the coatings were systematically investigated. The results indicated that the emissivity decreases significantly with increasing content of Cu powder and coating thickness. The coatings with smooth surface exhibit lower emissivity values than those with rough coatings. Moreover, we found the relationship between the emissivity of coatings and temperature presents a “U” type, and the emissivity reaches to the minimum at about 380 K. The mechanisms of low emissivity were proposed by optical theories, which are found to be in a good agreement with the experimental results. 相似文献
5.
ZnO:Al(AZO) thin films with different Al-doped concentration were developed under different temperature. The effects of the temperature and Al-doped concentration on the infrared emissivity were investigated. Results show that the crystalline phase of the AZO films is hexagonal wurtzite which is the same as that of the un-doped ZnO film. The crystalline size become larger and the particle shapes become more regular with the increase of temperature, which lead to the increase of resistivity and the decreases of the infrared emissivity. 相似文献
6.
Gong Shuxing 《International Journal of Infrared and Millimeter Waves》1990,11(11):1285-1297
ZnS antireflective coatings and passivation layer are developed on self-made PbTe/PbSnTe heterojunction infrared detectors and following experiments have been finished: WaterProof properties of ZnS coatings; Anti-reflective properties of PbSnTe materials and their detectors with ZnS coatings, respectively; ageing and stability tests of the PbSnTe detectors with ZnS coatings.All experimental results are excellent: The typical detectivity (D*) of PbSnTe detector is 2.83×1010 cmHz1/2W–1. (with peak wavelength p=9.8 m and cut-off wavelength c=11.7 m). Average detectivity of the PbSnTe detector with ZnS anti-reflective coatings is increased by 45%. Ageing tests indicated that the PbSnTe detectors with ZnS coatings have still high stabilities after several years. They are used successfully in medical infrared imaging systems and other applications. 相似文献
7.
Low emissivity is the complex system and polymer binder is one of the most important factors that affect optical and mechanical properties of the coating. Low infrared emissivity coatings were prepared by using flake aluminum particles and three types of polymer resins as fillers and binders, respectively. The influence of polymer binder viscosity on pigment particles distribution, surface morphology and infrared emissivity of the coating was systematically investigated. The results indicate that infrared emissivity of the coating can be strongly affected by the resin viscosity at the same preparation condition, which induces different aluminum particles distribution and surface morphology of the coating. Low resin viscosity is helpful for aggregating pigments and reducing the top polymer layer thickness near the surface, thus the infrared emissivity is reduced. If the resin viscosity value is decreased by two orders of magnitude, the infrared emissivity values would be reduced as much as 0.2. Additionally, a theoretical model is proposed to account for this mechanism, which indicates that sedimentation, evaporation and diffusion play important roles in forming different aluminum particles distribution during the drying process of the coating. 相似文献
8.
宽带减反射膜设计的一种新方法 总被引:1,自引:0,他引:1
提出实现宽带减反射膜系设计的新方法。该方法成功地设计出在可见光谱区的平均剩余反射率小于0.2%、减反射带宽390nm的四层等厚膜系;文中给出该法的理论推导、减反射限定条件及其应用的设计实例。结果表明,新的设计比传统三层减反射膜系设计具有明显的优越。 相似文献
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The main challenge of low infrared emissivity coatings based on aluminum flake lies in finding an efficient method to synthesize the composite pigment with low infrared emissivity and low lightness simultaneously. In this work, we overcome this constraint to some extent, synthesizing a novel Al/Co3O4 magnetic composite pigments with low infrared emissivity and low lightness by thermal cracking and hot flowing method. The results show that the covering area of Co3O4 on the aluminum flake can be tuned by the amount of CoCO3 adding in precursor and the reaction temperature of hot flowing, both of which pay a key factor on the VIS and IR spectral reflectance and magnetic properties. The magnetic Al/Co3O4 composite pigments with low lightness and low infrared emissivity can be obtained at 130 °C for 24 h in hot flowing liquid. The lightness L1 can be decreased to 69.2, however the infrared emissivity (8–14 μm) is also low to 0.45. Compared with the single Al flakes, Al/Co3O4 magnetic composite pigments present stronger magnetic properties. Therefore, the Al/Co3O4 magnetic composite pigments have offered new choice for the pigments of low infrared emissivity coatings. 相似文献
11.
Porous SiO2 antireflective (AR) coatings are prepared from the colloidal silica solution modified with methyltriethoxysilane (MTES) based on the sol-gel route. The viscosity of modified silica suspensions changes but their stability keeps when MTES is introduced. The refractive indices of modified coatings vary little after bake treatment from 100 to 150 ℃. The modified silica coatings on Ti:sapphire crystal,owning good homogeneity, display prominent antireflective effect within the laser output waveband (750-850 nm) of Ti:sapphire lasers, with average transmission above 98.6%, and own laser induced damage thresholds (LIDTs) of more than 2.2 J/cm2 at 800 nm with the pulse duration of 300 ps. 相似文献
12.
本研究利用纳秒激光两次双光束干涉无掩模烧蚀、快速制备硫化锌(ZnS)微纳结构抗反射疏水表面,使其红外透过率由原来的75%增加到92%,解决了表面淀积抗反射镀层膜层附着力、抗蚀性、热胀失配等问题.此方法加工过程快速简单,可实现大面积制作,且微纳结构使基底具有疏水性能,疏水角可达145fi.使其在光电子、太阳能、航空航天及红外制导等领域具有广泛的应用前景. 相似文献
13.
A. A. Ionin Y. M. Klimachev A. Y. Kozlov S. I. Kudryashov A. E. Ligachev S. V. Makarov L. V. Seleznev D. V. Sinitsyn A. A. Rudenko R. A. Khmelnitsky 《Applied physics. B, Lasers and optics》2013,110(3):419-423
Photoinduced linear electrooptical (EO) effect was studied for Zinc oxide nanofilms doped by Nd. We have chosen Nd rare earth impurity with different contents to explore its influence on photoinduced EO. The kinetics of the photoinduced EO changes was studied. We have chosen the bicolor coherent 10 ns Nd:YAG laser pulses with power densities varying up to about 1 GW/cm2 as the photoinducing beam. The enhancement of the photoinduced liner EO and its relaxation was explored. Additionally, the study of the photoinduced trapping levels within the energy gap was performed and the explanation of the obtained results is given. 相似文献
14.
根据红外辐射理论和薄膜光学原理计算了高品质ITO(indium tin oxide)导电膜的红外发射 率,其理论曲线与实测曲线基本符合. 并得出方块电阻小于30Ω时,ITO膜在红外波段8—14μ m的平均红外发射率理论值小于0.1.实际制备方块电阻小于10Ω的ITO膜具有优良的红外隐身 性能. 讨论了高品质ITO膜具有低红外发射率的物理机理,并提出了低红外发射率临界方块电 阻值,这有利於理论研究和工艺制备红外隐身ITO膜.
关键词:
红外发射率
ITO薄膜
理论计算
方块电阻 相似文献
15.
As a focus of research on materials science, bionic structure has drawn a great deal of attention from researchers. In this paper, patterned antireflection microstructure used for space optical window was fabricated on the surface of sapphire single crystal based on “Biomimetic Motheye Structure”. Meanwhile, emissivity of patterned sapphire at high temperature was investigated. The results indicated that transmittance of sapphire increased with spectrum red shift effect because of surface microstructures; the emissivity of patterned sapphire increased with rising of temperature in 6∼11 μm band; microstructures on surface led the scattering and attenuation coefficient of light to increase, thus, the emissivity of patterned sapphire was greater than that of contrast specimen which was not patterned. At the end of the paper, an audacious conclusion was made that the effect of microstructure on emissivity would decrease or even disappear with the increase of temperature. 相似文献
16.
《Current Applied Physics》2020,20(10):1163-1170
Biomimetic inspiration from the moth-eye structure has led to many studies combining nanoimprint lithography (NIL) to realize low cost and large area anti-reflection (AR) coatings. However, the scope of application is severely limited by poor mechanical performance due to the intrinsic properties of the coating materials and the nanosized patterns. In this work, we demonstrate a moth-eye structured epoxy-siloxane molecular hybrid (ME-ESMH) fabricated using single UV-based NIL (UV-NIL) on a colorless polyimide (CPI), to be utilized as a flexible cover window (FCW) for foldable displays. Low reflection, a superhydrophobicity and good inward foldability were achieved, together with excellent thermal and chemical resistance. Furthermore, in situ uniaxial compression tests revealed that the fabricated structure can be elastically deformed and nearly restored to its original shape even after a large degree of compression. Our findings provide an easy-to-integrate solution for flexible hard coatings with superhydrophobic and AR properties, applicable to foldable optoelectronics. 相似文献
17.
《Infrared physics》1990,30(4):331-342
A new method for contactless temperature measurement has been developed.(1) It is applied advantageously to highly reflecting objects of moderate temperatures (emitting no visible radiation), where conventional methods fail. A set of data is collected by radiance measurement m a number of n narrow spectral bands. These data represent numerical values for a set of analytical equations of the radiation emerging from the object. Solving the set of equations leads to u ⩽ n unknowns, which are the temperature of the object, its emissivity and the temperature of its environment. Balancing calculation enhances the accuracy. Software simulations, including the balancing calculation, the radiation transfer and the hardware of the prospected multispectral radiometer optimized the whole system prior to hardware development. The finally assembled laboratory model, a ten channel filter spectrometer, proved to function as predicted. The temperature of objects about 500 K and an emissivity as low as 0.03 has been determined with less than 1% deviation from thermocouple measurement. Measurement at lower temperatures and/or higher emissivities or higher temperatures and/or lower emissivities is possible with comparable accuracy. 相似文献
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The spectral radiant emissivity of tungsten ribbon ranging from 1 to 5. 1μ thick was measured in the temperature range from 1244–2441K. It was shown that the radiant emissivity of tungsten in the infrared region does not obey the Hagen-Rubens relation. 相似文献
20.
We studied infrared normal spectral emissivity on quasi-periodic microstructured silicon, which was prepared by femtosecond laser irradiation in SF6 ambient gas, coated with 100 nm thick Au thin film. The observed emissivity is higher than any reported previously for a flat material with a thickness of less than 0.5 mm, at a temperature range of 200 °C to 400 °C. The emissivity over the measured wavelength region increases with temperature and the spike height. These results show the potential to be used as a flat blackbody source or for applications in infrared thermal sensor, detector, and stealth military technology. 相似文献