Flat Absorber Phosphorous Black Nickel Coatings for Space Applications

A new process of flat absorber black nickel alloy coating was developed on stainless steel by electrodeposition from a bath containing nickel,zinc and ammonium sulphates;thiocyanate and sodium hypophosphite for space applications.Coating process was optimized by investigating the effects of plating parameters,viz concentration of bath constituents,current density,temperature,pH and plating time on the optical properties of the black deposits.Energy dispersive X-ray spectroscopy showed the inclusion of about 6% phosphorous in the coating.The scanning electron microscopy studies revealed the amorphous nature of the coating.The corrosion resistance of the coatings was evaluated by the electrochemical impedance spectroscopy (EIS) and linear polarization (LP) techniques.The results revealed that,phosphorous addition confers better corrosion resistance in comparison to conventional black nickel coatings.The black nickel coating obtained from hypophosphite bath provides high solar absorptance (α s) and infrared emittance (ε IR) of the order of 0.93.Environmental stability to space applications was established by the humidity and thermal cycling tests.     

等离子喷涂法制备黑铬太阳能选择性吸收涂层

采用等离子喷涂法制备了黑铬太阳能选择性吸收涂层,采用XRD、SEM等测试方法对涂层的物相、微观结构、太阳能吸收性能进行了表征。对涂层进行了打磨,并在涂层表面制备SnO2选择性透过薄膜。研究表明,采用等离子喷涂方法制备的黑铬涂层吸收率为0.93,发射率为0.88,经打磨处理后,发射率降至0.76。添加SnO2薄膜后,涂层吸收率变化小,发射率降至0.50。热震实验表明该涂层具备良好的抗热震性能。     

真空管式太阳能集热器研究最新进展

从选择性吸收涂层的材料、结构、热稳定性及真空环境等方面综述了真空管式太阳能集热器的研究进展。不锈钢、Ti、Al、Ni类材料适于制备中低温选择性吸收涂层;而Mo和W类等高熔点材料,适于高温涂层。涂层结构方面,主要有吸收层/介质减反层的光干涉类、金属红外反射层/金属介质吸收层/介质减反层的金属陶瓷类。影响涂层热稳定性的主要因素是高温下涂层的破裂、氧化及元素扩散,涂层厚度与结构也能影响热稳定性。结果表明:①选择性吸收涂层制备,应采用电化学或磁控溅射技术并结合纳米材料对涂层进行多层化、梯度化研究;②应着重发展Mo类金属陶瓷型的热稳定性好的涂层,以实现高温高效集热;③应加快实现太阳能集热器的智能化、自动化与建筑一体化。     

电沉积法制备碳纳米管/黑镍复合涂层的光学与结构特性

利用复合电沉积的方法在钛合金基体上成功制备出具有优异光学性能的碳纳米管／黑镍复合涂层, 并研究了复合涂层的微观形貌、光学性能以及镀液中碳纳米管浓度和电镀电流密度对光学性能的影响。实验结果表明: 相较于传统电镀方法获得的单一黑镍涂层, 复合涂层的晶粒尺寸明显减小, 形成多孔结构, 表面粗糙程度明显增加。复合涂层对300~2300 nm范围内的入射光吸收率达到98%左右, 在2.5~20 μm范围内的红外吸收率达到94%, 远远高于传统单一黑镍涂层。复合涂层的太阳吸收比会随着镀液中碳纳米管浓度与电镀电流密度的增加呈先增大后减小的变化规律。     

直接吸收式太阳能集热纳米流体光热特性研究

采用两步法配制了Co-H2O纳米流体,针对不同粒径、不同质量分数、不同pH值的纳米流体,与去离子水一起同步测试了其光热转换特性。实验结果表明:纳米流体的温升速率及集热量明显优于去离子水的。纳米流体质量分数有一最佳值,实验中质量分数为0.1%时效果最好,其最高温度要比纯水高出30.3%。30 nm Co-H2O纳米流体的光吸收能力要强于50 nm Co-H2O纳米流体的。pH值对光热特性有较大影响,实验中p H=8效果最佳。Co-H2O纳米流体优异的光吸收性能表明其有望运用在直接吸收式太阳能系统中。     

平板太阳能集热器强化传热特性研究

介绍平板太阳能集热器的典型结构、传热特性及数学模型,综述平板太阳能集热器改进透明盖板,设置透明隔热层,改进吸收涂层,优化吸热板、采用纳米流体等强化传热措施及发展趋势。     

A Spectral Emissivity Measurement Facility for Solar Absorbing Coatings

A new facility that uses integrating-sphere reflectometry to measure the spectral emissivity of solar absorbing coatings in the range from 0.4μ m to 10 μm and in the temperature range from 300 K to over 900 K has been built at the Harbin Institute of Technology. The technique is based on a system previously developed at the National Institute of Standards and Technology. Measurements have been performed on two different coatings. The results are in good agreement with those obtained by the method of radiant energy comparison using a Fourier transform infrared spectrometer. Emissivity measurements performed with this facility present an uncertainty of 5.3 % (coverage factor = 2).     

铝合金专用黑色耐磨涂料的研制

针对黑色阳极氧化膜层的修复研制了一种专用耐磨涂料，该涂料可直接喷涂在原阳极氧化膜层上，热固化成膜，膜层硬度高、耐磨性好，具有较优良的综合性能，解决了表面修复的难题，该涂料也可应用在其他金属材料的表面防护上。     

镍基夜光颜料发光复合镀层的研究

研究了用瓦特镀镍淤电沉积夜光颜料发光复合镀层的工艺，讨论了镀液中阴极电流密度、夜光颜料微粒含量、电镀温度、pH值以及搅拌速度对镀层中夜光颜料复合量的影响。结果表明，选择适当的工艺参数可以获得结合力强、耐 性好、发光强度高的镍基夜光颜料发光复合镀层。     

Electrodeposition of High-Purity Molybdenum Coatings on Nickel1

High-purity molybdenum coatings suitable as matrix materials for superconducting microwave systems were prepared on nickel substrates by electrodeposition from a CaCl₂–CaMoO₄–CaO melt. The contamination of molybdenum with nickel was found to be insignificant, so that, in producing matrices for microwave applications, the required coating thickness depends only on subsequent mechanical or other treatments.     

太阳能光谱选择性吸收涂层研究进展

采用高速研磨搅拌加水掺法,制备出含不同质量分数的纳米SiO2混杂纤维（NSPF）混凝土,通过力学试验测得立方体抗压强度、劈裂抗拉强度、变形性能及冲击韧性。通过与钢纤维／聚丙烯二元混杂纤维（SPF）混凝土进行比较,NSPF混凝土的立方体抗压强度、劈裂抗拉强度、疲劳次数、弹性模量、初裂抗冲击次数和破坏抗冲击次数分别提高10...     

The Deposition of Improved Nickel Coatings on Kovar Articles

A technology for depositing a nickel–carbon alloy is briefly described, and a scheme for preparing kovar articles before coating is considered.     

电沉积Zn-Ni多层膜的Ni含量及显微硬度

通过单槽法成功制备出了Zn-Ni多层膜,利用扫描电镜SEM观察Zn-Ni多层膜的截面微观形貌,同时通过随机配带的X射线成分分析仪对镀层的镍含量做了分析;研究了平均电流、占空比、调制波长对多层膜硬度的影响。结果表明:峰值电流对多层膜中Ni的含量影响很大,峰值电流高时,Ni含量高;多层膜硬度也随峰值电流的增大而增大。     

Fabrication of Porous Tantalum and Tungsten Black Coatings for Artificial Earth Satellites

Technical Physics Letters - Coatings are fabricated using plasma-ion sputtering and codeposition of ultradispersed Ta and Cd particles and Nb- and Mo-doped W and Cd particles. The fabricated...     

Photothermal Characteristics of Novel Flexible Black Silicon for Solar Thermal Receiver

In this article, a novel type of flexible black silicon used for enhancing the absorption of a solar thermal receiver is reported. The optical absorption properties of this kind of flexible black silicon with three different sizes of conical microstructure are analyzed using the finite-difference time-domain (FDTD) method and the heat transfer properties are studied using the COMSOL multiphysics heat transfer solver. The results show that flexible black silicon with small-size microstructure has the highest optical absorptance and heat transfer speed. A commercial silicon-on-insulator wafer is irradiated by an auto-scanning femtosecond laser system and then split by etching out its middle layer in 52?% hydrofluoric acid to fabricate the flexible black silicon. The obtained flexible black silicon presents very good flexibility, and its photothermal characteristics are investigated. The optical absorption spectrum test results indicate that the absorptance of the flexible black silicon is as high as 97?% in the visible spectral region and is higher than that of anodized aluminum in a broad spectral range from 250?nm to 2500?nm. The light radiation heating experiment results show that the energy absorption efficiency of the water covered with flexible black silicon is improved 13?% compared with that of the water covered with anodized aluminum. It is confirmed that as a light-absorbing and heat-transferring layer the flexible black silicon has an important potential application in exploring solar energy.     

Solar Process for Surface Glazing of Zirconia-Based Plasma Sprayed Thermal Barrier Coatings

A solar process for thermal barrier coatings surface glazing is presented. Results obtained on an yttria partially-stabilized zirconia plasma sprayed coating are described. The optical behavior of the ceramic during the thermal treatment is also discussed.     

Theoretical Analysis of Spectral Selective Transmission Coatings for Solar Energy PV System

Spectral selective transmission coatings can adjust the spectrum of incident solar radiation to reduce the waste heat generation in solar cells and to improve solar photovoltaic conversion efficiency. The ideal spectral transmissivity of the coatings should match the spectral response of solar cells, which means the ideal spectral transmissivity should be equal to 1.0 in the range of the spectral response and 0 in the other spectrum. The reflection performance of the three kinds of spectral selective transmission coatings for silicon solar cells are designed and analyzed. The results indicated that the ZnS/Na₃AlF₆ coating systems have a wider reflected infrared (IR) region than the TiO₂/SiO₂ coating systems, but lower transmissivity in the wavelength range of 0.5 μm to 1.1 μm. Furthermore, an Nb₂O₃/SiO₂ coating system is proposed and optimized, which has 31 layers with a smaller total thickness of 2.675 μm. The radiative properties including reflectivity and transmissivity of spectral selective transmission coatings are investigated and theoretically analyzed.     

多层镍镀硬铬爆皮产生之因及消除法

多层镍镀硬铬是近年兴起的镀种，它具有多层镍层的高耐蚀性，又具有硬铬层的高硬度和高耐磨性，是性能优良的功能性镀层，常用于条件恶劣，硬度、耐磨性要求高的产品，如汽车、摩托车的减震器。这种镀层结构为总镍层厚度１５～２０μｍ，硬铬层１０～１５μｍ，半光亮镍层和光亮镍层之间的电位差在１２０ｍＶ以上，高硫镍层含硫量在０．１５％左右，硬铬层硬度达８００ＨＶ以上。和普通多层镍铬工艺相比，它的要求要高得多。普通多层镍铬电镀线上镀硬铬会出现大面积爆皮现象（既出现在基体同镀层之间，也出现在镍层和硬铬层之间）。试验认为…     

Effect of Electroplating Parameters on Microstructure of Nanocrystalline Nickel Coatings

In order to achieve the optimum conditions for electroplating nanocrystalline nickel coating from Watts-type bath, the effect of some process parameters namely, bath temperature, current density, and saccharin addition on grain size and texture coefficient (TC= I(200)/I(111)) of the deposits were investigated by X-ray diffraction (XRD). The results showed that in a bath containing 5 g/L saccharin, by increasing the bath temperature from 45°C to 55°C, the grain size decreased, whereas further increase of bat...