Co-Cr3C2-WC/Al2O3太阳能选择性吸收涂层制备与性能研究  

Preparation and Properties of Co-Cr3C2-WC/Al2O3 Solar Selective Absorbing Coatings

作　　者：邵豪 曾鲜 李擎煜 刘富生 刘统治 程旭东[1] SHAO Hao;ZENG Xian;LI Qing-yu;LIU Fu-sheng;LIU Tong-zhi;CHENG Xu-dong(Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学,武汉430070

出　　处：《表面技术》2020年第6期138-145,共8页Surface Technology

摘　　要：目的研究不同比例的Co-Cr3C2-WC吸收层的光谱发射与吸收性能,并在吸收层表面制备Al2O3减反膜,进而得到一种新型中高温金属-陶瓷型太阳能选择性吸收涂层。方法采用超音速火焰喷涂法(HVOF)在不锈钢基底制备Co-Cr3C2-WC吸收层,并对其成分比例进行优化,再通过溶胶-凝胶法(Sol-Gel)在吸收层表面制备Al2O3减反膜。通过X射线衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)等,对涂层的物相、元素价态、微观形貌进行表征分析。采用表面粗糙度仪测量涂层的表面均方根粗糙度。利用傅里叶红外光谱仪和紫外可见分光光度计分别测量涂层在远红外波段和紫外可见近红外波段的光谱反射率。结果90Co-5Cr3C2-5WC(wt.%)吸收层具有最高的品质因子(吸收率/发射率α/ԑ=0.805/0.308),且表面增加Al2O3减反膜后的涂层吸收率增加至0.903,发射率降低至0.278。涂层表面均匀致密,表面粗糙度Ra降低到1.109μm。在750℃大气环境下热处理100 h后,涂层吸收率增大到0.910,发射率为0.315,选择吸收性能稳定。结论90Co-5Cr3C2-5WC吸收层在保持较高的吸收性能下,有效地改善了热喷涂涂层的表面状态,降低了吸收层的发射率。Al2O3减反膜通过增大短波段光的透过作用以及封孔作用,进一步增大了复合涂层的吸收率,提高了涂层的选择吸收性能和高温服役性能。有望作为中高温太阳能集热系统中的选择吸收涂层材料。The work aims to study the spectral emission and absorption properties of different Co-Cr3C2-WC absorbing layers and prepare Al2O3 anti-reflection films on the surface of the absorbing layer to obtain a novel mid-high temperature cermet-based solar selective absorbing coating.The Co-Cr3C2-WC absorbing layers were deposited on the stainless steel by high velocity oxygen-fuel spraying technology(HVOF),and the components were optimized.The Al2O3 anti-reflection films were then prepared on the surface of the absorbing layer by Sol-Gel method.The phase composition,elemental valence and micro-structure of the coatings were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM),separately.The root mean square roughness was measured by a surface roughness meter.The spectral reflectance of the coatings in the UV-Vis-NIR and far infrared bands was measured by Fourier infrared spectrometer and UV-Vis-NIR spectrophotometer,respectively.90Co-5Cr3C2-5WC(wt.%)absorbing layer had the highest quality factor(α/ԑ=0.805/0.308).In addition,the absorptance of the coating increased to 0.903,and the emittance decreased to 0.278 after Al3O2 anti-reflection films were added on the surface.The coating surface was dense and uniform and the roughness was reduced to 1.109μm.After 100 hours of heat treatment at 750℃in air,the absorptance of the coating increased to 0.910 and the emittance was 0.315,indicating stable selective absorption performance.The 90Co-5Cr3C2-5WC absorbing layer effectively improves the surface state of the thermal sprayed coating and reduces the emittance of the absorbing layer while maintaining a high absorption performance.The Al2O3 anti-reflection film further improves the absorptance of the composite coating by increasing the transmittance of short-wave light and sealing effect,thus enhancing the selective absorption and high-temperature serviceability.Therefore,such coating is expected to be used as a selective absorbing coating in mid-high temperature

关 键 词：Co-Cr3C2-WC/Al2O3 选择性吸收涂层 光学性能 热稳定性 超音速火焰喷涂 溶胶-凝胶法 

分 类 号：TG174.4[金属学及工艺—金属表面处理]