等离子喷涂与溶胶-凝胶法组合制备中高温太阳能选择性吸收复合涂层

为了制备出高效的非真空、中高温太阳能选择性吸收涂层,先在光亮Cu片上等离子喷涂Cr—Al2O3金属陶瓷吸收层,再用溶胶-凝胶法在其上制备了SnO2选择性透过膜,对复合涂层的相结构、表面形貌、光学性能进行了研究。结果表明：金属陶瓷吸收层由金属颗粒Cr与Al2O3组成,物相稳定,表面凹凸不平,气孔较多,发射率较高;覆盖Sn...     

真空镀膜制备太阳能热吸收涂层

本文介绍了选择性太阳能热吸收涂层的制备方法及发展状况,重点描述了真空镀膜在金属卷材上制备选择性太阳能热吸收涂层。该涂层用在平板太阳能集热器上,促进了太阳能集热器由单一的真空玻璃管型向金属平板型的转变。     

先进高温选择吸收涂层材料及其稳定性研究

从高温选择吸收涂层材料的热力学基础、研究现状及热稳定性研究等方面简要阐述了先进高温选择性涂层的发展以及存在的问题。在高温选择吸收涂层材料及热稳定性研究方面,高熔点及耐氧化性的过渡族金属陶瓷材料经常是高温涂层的首选。此外,纳米晶、非晶以及多层膜结构等也对涂层的光学性能及热稳定性有积极作用。针对商业化应用,在后期的研究中还应继续解决涂层材料的高发射率及高温热不稳定等关键问题。     

真空镀膜平板太阳能集热器的应用前景

主要介绍了平板集热器的结构、特点以及平板集热器板芯选择性吸收涂层的几种制备方法,真空磁控溅射制备选择性吸收涂层,提高光热效率和涂层的使用寿命,具有膜层均匀、致密、生产环保等特点。适合于连续式工业化生产,作为建筑材料,实现太阳能利用与建筑一体化,是新一代太阳能集热产品。     

提高太阳能集热管磁控溅射镀膜沉积速率的研究

工业上用磁控溅射技术为太阳能集热管制备Al-N/Al选择性吸收涂层,这种吸收涂层最外层为AlN介质减反层.在开环N2流量控制模式下,存在溅射制备AlN介质减反层沉积速率低的缺点.本文依据气相化学反应动力学理论,薄膜的沉积率正比于反应气体的浓度,提出了一种提高制备AlN陶瓷减反层沉积速率的方法.该方法将直流溅射靶电压反馈至模糊控制器,控制N2流量大小,让磁控溅射镀膜机稳定工作在拐点电压附近,实现反应溅射恒电压控制.并且采用单片机技术制作了样机,在SCS-700A型太阳能集热管镀膜机中使用,实验结果表明,镀膜沉积速率提高了4倍以上,整个系统工作稳定.     

中高温太阳能选择性吸收涂层的研究进展

近年来太阳能中高温选择性吸收涂层的研制及应用成为人们关注的焦点。对中高温涂层的国内外研究现状做了详细描述,着重介绍了金属陶瓷吸收涂层和半导体金属光干涉涂层,并提出一种新型的具有核壳结构纳米级金属陶瓷复合涂层,理论上其具有很好的光学性能及高温稳定性。     

碳化物超高温陶瓷太阳能选择性吸收涂层的研究进展

太阳能选择性吸收涂层是将太阳辐射选择性吸收转化成热能的材料.为更大限度地利用太阳能,高温太阳能选择性吸收涂层成为提高光热转化效率的关键部件.碳化物超高温陶瓷因具有良好的光学性能和高温稳定性而成为优选材料.目前,很多研究者已通过磁控溅射法、热喷涂法、溶胶凝胶法和激光涂覆法等方法制备了多种碳化物陶瓷基太阳能选择性吸收涂层,并且做了大量的工作来优化其性能.本文综述了碳化物陶瓷基太阳能选择性吸收涂层的研究进展,介绍了太阳能光谱选择性的要求及其选择性吸收的基本原理,总结了碳化物陶瓷基太阳能选择性吸收涂层的制备方法、材料、性能及其重要影响因素,最后展望了碳化物超高温陶瓷太阳能选择性吸收涂层的发展前景.     

新一代太阳能集热板真空镀膜生产线系统的开发

本文介绍了新一代太阳能集热板真空镀膜生产线系统组成及其主要结构的特点。该系统制备的集热板选择性吸收涂层具有良好的光热性能、力学性能和耐候性能;提高集热板光热效率和涂层的使用寿命并实现了集热板集热涂层生产的环保化和连续化,对平板集热器的发展和应用具有极大的推动作用。     

TiAlN/SiO2太阳能选择性吸收薄膜的制备与研究

采用直流磁控溅射法在铜基底上制备了TiAlN/SiO2选择性吸收薄膜。通过调整制备过程中的工艺参数,得到优化后的组合薄膜(铜基底),其吸收率可达0.92、发射率为0.06。在此组合膜系中,TiAlN为吸收层,SiO2为减反层。对基底为铜片的样品在550℃退火2h,其性质保持稳定,表明TiAlN/SiO2组合薄膜在高温太阳能选择性吸收领域具有一定的应用前景。     

高性能SS-AlN金属陶瓷真空太阳集热管的制备

采用真空磁控溅射沉积SS-AlN金属陶瓷太阳选择性吸收涂层.涂层光学功能层的制备,先采用铜靶溅射Cu红外反射层;再采用不锈钢(SS)和铝两金属靶在Ar和N2的混合气体中同时溅射沉积SS-AlN金属陶瓷吸收层;最后采用Al靶在Ar和N2中反应溅射沉积AlN减反射层.金属陶瓷吸收层由高、低SS体积份额的两吸收子层组成.优化溅射镀膜工艺参数获得高性能吸收涂层,太阳吸收比α(AM1.5)高达0.956±0.003(国标GB:α≥0.86),比GB高10％;红外发射比ε仅为0.043±0.003(GB:ε≤0.08).制备成φ58×2100 mm全玻璃真空太阳集热管,80℃平均热损系数ULT仅为0.47±0.01 W/m2℃ (GB:ULT≤0.85 W/m2℃),比GB低0.38W/m2℃,性能提高45％.制备的真空集热管具有良好的真空品质,集热管内管加热350℃恒温480 h后,吸气镜面轴向长度平均消失率仅为2～3％,集热管真空品质优于GB高达100倍以上(GB:350℃恒温48 h,镜面消失率≤50％).     

Quasicrystal films: numerical optimization as a solar selective absorber

Selective absorbers for solar thermal energy applications have to show high solar absorptance _s and low thermal emittance ε_h. Stability against oxidation and diffusion is indispensable, especially at high absorber temperatures. The new class of quasicrystalline materials seems to have favourable properties regarding stability. With a genetic algorithm a thin film stack based on dielectric and quasicrystal films was optimized as a selective absorber. A sandwich system dielectric/quasicrystal/dielectric on copper has highly selective properties: _s = 0.86 and ε_h (400 °C) = 0.051. Even better results can be achieved, at least in theory, by the use of a cermet. The optical constants of cermets with the quasicrystalline material as the metal were calculated with the Bruggeman theory. A system of a cermet film and an additional antireflective coating on copper shows _s = 0.92 and ε_h (400 °C) = 0.048.     

Preparation of solar selective absorbing coatings by magnetron sputtering from a single stainless steel target

This paper presents a method to prepare solar selective absorbing coatings by radio frequency magnetron reactive sputtering using a single stainless steel target. Stainless steel/stainless steel nitride (SS/SS-N) ceramic-metal composite (cermet) thin films were produced under varied nitrogen gas flow ratios. The solar selective absorbing films have good solar absorptance of 0.91 and thermal emittance of 0.06 at 82 °C. The refractive index (n) and extinction coefficient (k) of the cermet composite layers prepared in nitrogen and argon atmospheres were determined by spectroscopic ellipsometry. The films were also analyzed by different oscillator models. The results showed a significant transformation from metal to cermet as the nitrogen gas flow ratio was increased to 10%. As the nitrogen gas flow ratio was increased to 17.5%, the film became a dielectric layer that could be used as an anti-reflection layer, suitable as the outermost layer of the solar selective absorbing coatings. A theoretical solar absorptance of 0.92 was achieved by selecting an appropriate combination of three solar absorbing layers. The experimental results agreed well with the theoretical calculations. This study proved the possibility of preparing solar selective absorbing coatings with high solar absorptance by using a single stainless steel target.     

Hochselektive Absorberschichten für thermische Sonnenkollektoren

High‐selective absorber coatings for solar thermal collectors Highly selective absorber coatings are necessary for the effective operation of state‐of‐the‐art solar thermal collectors. The thin film gradient optical coating with its spectrally selective characteristics achieves high solar absorptance combined with low thermal emittance. Such complex multi‐layer systems are produced in modular vacuum coating processes. Industrial air‐to‐air coating lines allow the continuous coating of metal bands in a pass‐through process and provide absorber coatings which meet highest demands for efficiency, durability and esthetics.     

4.3 Vacuum evaporated thin films for solar collectors

Selectively absorbing surfaces are important for the efficient use of solarenergy. The main characteristics aimed at for this type of coatings are the highest possible absorptivity for solar radiation and the lowest possible emissivity for thermal radiation. (Temperatures up to 100–200°C). There are several ways to create surfaces with these properties. In the present work evaporated semiconductor films with suitable anti-reflection coatings were used on different metals. For the laboratory tests, the metals were vacuum evaporated on glass substrates. The evaporations were performed with an electron beam gun in a diffusion pumped system. The evaporated thicknesses and the rate of evaporation were controlled by a quartz crystal monitoring system. The selective coatings were studied on flat and rough metal surfaces. Sinusoidal, metal covered gratings with different periods were used as the rough absorber surfaces. This simplified the measurements of absorptivity and emissivity and gave a more thorough understanding of the basic thin film phenomena. It is possible to use gratings because the general rough surface can be looked upon as a superposition of different sinusoidal gratings. A comparison is made between the properties of the layers on flat and rough surfaces. The coatings were subjected to high humidity and high temperature tests. They were also cycled between the intended working temperature and ambient temperature to check possible degradation. Results concerning film adherence and stability during these environmental tests are given.     

微带方形开口环的高效太赫兹波吸收器研究

设计了一种基于微带方形开口环结构的太赫兹波吸收器,它由顶层方形开口环、中间电介质层基体和底层金属板组成.提出一种等效电路模型,利用该模型完成了对太赫兹波吸收器的设计、加工与测试.研究结果表明,吸收器在0.575THz处吸收率高达0.993.通过对器件的物理尺寸及材料参数的灵活调节,经优化设计即可实现对不同频率入射电磁波的高吸收.该吸收器具有结构简单、体积小、吸收率高等优点,有望在频谱成像、热辐射探测等应用中发挥重要作用.     

Fabrication and optimisation of highly efficient cermet-based spectrally selective coatings for high operating temperature

In terms of both high photo-thermal efficiency and high stability, multi-layer structures based on metal-dielectric composites (cermet) can be considered the most attractive selective solar absorbers for receiver tubes operating at medium-high temperatures in the field of solar thermodynamic plants. The double cermet layer approach represents a very simple fabrication method and can give high performances in terms of high solar absorptance and low hemispherical emittance. Optimised solar coatings based on cermet layers were fabricated in our laboratories by sputtering technique following the double layer approach. The joined employment of ellipsometric measurements and optical simulation is proposed as an effective method to optimise and fabricate coatings showing the best performances at a fixed operating temperature of the receiver tube. Interesting results concerning an optimised spectrally selective coating are shown. Solar absorptance higher than 0.94 and hemispherical emittance at 580 °C lower than 0.13 were obtained.     

直流反应溅射沉积Al2O3薄膜及其在SS-AlN金属陶瓷太阳吸收涂层的应用

在沉积不锈钢-氮化铝(SS-AlN)金属陶瓷太阳吸收集热管的磁控溅射三靶镀膜机上,安装了UPS03反应溅射闭环控制单元,实现反应溅射Al2O3稳定反馈控制。采用国产直流电源在Al靶表面处于过渡态下,成功制备了吸收几乎为零的Al2O3薄膜。溅射功率在14kW时,反应溅射沉积Al2O3的靶电压波动可长时间稳定控制在±3 V范围内,沉积速率为5.4 nm/(min·kW),约为Al靶在无反应气体溅射下沉积Al薄膜速率的74%。采用Al2O3代替AlN作为减反射层,应用到SS-AlN太阳选择性吸收涂层中,进一步提高了复合膜的太阳光学性能,太阳吸收比由AlN作为减反射层的0.956提高到0.965,红外发射比不变,仍为0.044。     

Eine Cermet-Glasschmiermittelkombination für Reibpaarungen bei Arbeitstemperaturen von 650–1100°C

A cermet/lubricating glass-combination for friction pairs at working temperatures 650–1100°C The function and the efficency of technical plants are limited by the used materials and their behaviour under working conditions. At elevated temperatures, the corrosion and wear resistance and the thermal shock behaviour are as necessary as mechanical stability at high operating temperatures. Metals and ceramics often cannot meet the conditions. Dynamic applications may require lubricatings, metals surfaces may be too soft and not very oxidation-resistant. Metal-ceramic materials, -cerments-, use a combination of the properties of their microstructural parts. This paper shows a combination of a cermet and a lubricating glass with interesting aspects for high temperature operation.     

泪滴状铝纳米结构紫外-近红外宽带吸收体的制备

宽波段光吸收体在太阳能利用、光探测等领域具有重要的应用价值.本研究以带铝基的多孔氧化铝(AAO)膜为模板,采用真空电子束蒸镀技术,结合后续的高温退火、湿化学刻蚀和胶带剥离等处理过程,制备出了泪滴状铝纳米结构宽带吸收体,其吸收率在200～980 nm的波长范围内均高于93％,在紫外光谱区的吸收带宽大于文献中报道的单一金属...