钨-氮化铝太阳能选择性吸收表面的研制

A Study on the Surface Coating of W-AIN for the Selective Absorption of Solar Energy

为了改善太阳能选择性吸收表面的中高温性能；采用掺钨的氨化铝金属陶瓷复合材料作为太阳能选择性吸收涂层。根据复合材料的有效介质理论；对金属陶瓷膜系的光学性能进行理论计算；采用磁控多靶反应共溅射的方法对膜系进行反演寻优工艺实验；在对复合膜的金属粒子体积分数ｆ、厚度ｄ进行多次组合实验后，取得了制备最佳组合膜系的溅射工艺参数。实验结果表明；必须利用金属陶瓷吸收层与基底金属的干涉效应，再加减反射层才能得到理想的选择性吸收效果，吸收率 ａ＞０．９，发射率ε（３５３Ｋ）＜０．１。当温度高于３５０℃时性能稳定，吸收率α变化不大，而发射率ε不超过０．１。与多层渐变吸收涂层相比；金属陶瓷选择性吸收涂层具有膜系结构简单、膜层减少、膜厚降低等优点。该涂层适用于低倍聚光式真空管集热器。

in order to improve the moderate and high temperature properties of surface for selective absorption of solar energy a coating of W-AIN cermet composite material was adopted. Based on the theory of effective media of composite material, the optical property of cermet films was calculated and the optimization experiments were carried out using the reaction co-sputtering method of magnetron sputtering with multi-targets. Through repeated experiments for varying the volume fraction of metallic particles f and thickness d of composite film, the optimum sputtering parameters were obtained. The experiment results showed that to make use of the cermet absorption layer and the interference effect of substrate, and the reflection layer is necessary to reach the optimum effect of selective absorption; absorption rate α >0.9, specific emission E (353K)<0.1, with stable property when temperature over 35℃.Compared with the multilayered graded absorption coating, cermet coating possesses the advantages of simple structure, reduced layers and thickness.