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本文介绍了用于全玻璃真空管太阳能集热器的真空沉积双层黑铬选择性涂层的工艺和性能。其α_s为89％—91％,ε_n为5％—7％(80℃)。该涂层经300℃—400℃、1小时的烘烤后,α_s和ε_n基本没有变化。 应用激光干涉法,在λ=6328(?)波长下对每层黑铬涂层的光学常数进行了初步测定,并用测定的数据计算了该波长下双层涂层的反射率,其结果与分光光度计测定的反射率基本相符。结果表明,第二层黑铬具有减反射作用,因而使真空沉积的双层黑铬选择性涂层具有较高的吸收率,并仍保持其低的红外发射率。 还应用了电子显微镜、电子衍射与x光衍射等对黑铬选择性涂层进行了表面形貌观察与物相分析。 对所试制的真空沉积双层黑铬真空集热样管的试验表明,涂双层黑铬的真空集热管的集热性能优于单层黑铬的集热管。
This article describes the process and performance of a vacuum deposited double black chromium selective coating for all-glass vacuum tube solar collectors. Α_s is 89% -91%, and ε_n is 5% -7% (80 ° C). After the coating was baked at 300 ℃ -400 ℃ for 1 hour, there was almost no change in α_s and ε_n. The optical constants of each layer of black chrome coating were preliminarily determined by laser interferometry at λ = 6328 (?), And the reflectivity of the double layer coatings at this wavelength was calculated using the measured data. The results were compared with spectroscopy The reflectance measured by the photometer basically matched. The results show that the second layer of black chrome has an antireflection effect, so that the vacuum deposited black chrome selective coating has a higher absorption rate, while still maintaining its low infrared emissivity. Electron microscopy, electron diffraction and x-ray diffraction were also applied to the surface morphology and phase analysis of the selective coating of black chromium. Experiments on the vacuum-deposited double-layer black-chrome vacuum collector sample of the vacuum-deposited double-layer vacuum chilled vacuum tube show that the heat-collecting performance of the double-layer black chrome vacuum tube is better than that of the single-layer black chrome collector tube.