Mo-Al_2O_3光谱选择性吸收涂层的制备及热稳定性  

Preparation and thermal stability of Mo-Al_2O_3 spectrally selective absorbing coatings

作　　者：张敏[1] 张文辉 李影 殷雪 李美仪 李小晶 郭媛媛 ZHANG Min;ZHANG Wenhui;LI Ying;YIN Xue;LI Meiyi;LI Xiaojing;GUO Yuanyuan(School of Physics and Electronic Technology,Liaoning Normal University,Dalian116029,China;School of Materials Science & Engineering,University of Science and TechnologyLiaoning,Anshan 114051,China)

机构地区：[1]辽宁师范大学物理与电子技术学院,辽宁大连116029 [2]辽宁科技大学材料科学与工程学院,辽宁鞍山114051

出　　处：《辽宁师范大学学报（自然科学版）》2018年第4期462-469,共8页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家自然科学基金资助项目(51101080;51502126)

摘　　要：光谱选择性吸收涂层是提高太阳能光热转换效率的核心部分,其在太阳光能量集中的光谱波段保持较高吸收率,同时拥有较低的红外发射率,即减少自身向外辐射的能量.选用直流-射频磁控溅射镀膜的方法,在抛光的316L不锈钢基片上制备了以金属Mo为红外反射层,Mo-Al_2O_3为吸收层,Al_2O_3为减反射层的Mo/Mo-Al_2O_3/Al_2O_3选择吸收膜系,并对其进行大气中400℃退火处理,分析其热稳定性和选择吸收性能的衰减机理.通过实验优化,具有双吸收层结构的选择吸收膜系具有最优的选择吸收性能,吸收率为0.922,发射率为0.029.所制备的薄膜表面平整致密,无明显的大颗粒缺陷.对优选制备参数下的选择吸收膜系进行退火处理,结果表明退火后选择性吸收膜系的发射率上升约1.6%,膜系的反射率极小值的位置与退火前无明显变化,反射率骤升阈值均发生蓝移.利用拉曼光谱对太阳能选择性吸收膜系的高温热稳定性进行分析,当退火时间为1、3h时,开始出现了MoO_3特征峰,说明空气中的氧原子向吸收层中进行了扩散,当退火时间达到5h时,出现了Fe_2MoC的特征峰,说明吸收涂层各亚层之间的元素发生了迁移.The spectrally selective absorbing coatings are the key component for enhancement of conversion coefficient in solar-thermal applications.The coating exhibits high absorbtance upon solar spectral,while low emittance in infra-red spectral to reduce the energy loss due to radiation.In this paper,metal Mo selected as the infrared reflective layer,Mo-Al2O3as the absorbing layer and Al2O3as the antireflective layer,the Mo/Mo-Al2O3/Al2O3metal-medium thin film was fabricated on polished316L stainless steel by using magnetron sputtering.The thermal stability and the degrade mechanism of selective absorbing performance were analyzed by annealing at400℃in air.The optimization results show that the coatings with dual absorbing layers exhibit better selective absorbing property with an absorptance of0.922and an emittance of0.029.The obtained film has a smooth and dense surface,without any apparent macro-particle defects.The results of annealing show that the emittance of the annealed samples increases by1.6%.The position of the minimum of the reflectance almost keeps the same before and after annealing.The increasing threshold of the reflectance appears blue-shift.Raman spectroscopy was applied to analyze the high-temperature thermal stability.When the annealing time reaches1h and3h,the characteristic peaks by molybdenum oxides with different valences begin to appear,showing the oxygen in air has diffused inward the absorbing coating.When the annealing time is5h,a Fe2MoC characteristic peak appears,showing element migration in absorption coating happens between each sublayer.

关 键 词：光谱选择性吸收涂层 磁控溅射 热稳定性 吸收率 发射率 

分 类 号：TB34[一般工业技术—材料科学与工程]