Study on the thermal stability of Al/NbTiSiN/NbTiSiON/SiO2 solar selective absorbing coating. (September 2015)

• Record Type: Journal Article
• Authors: Wu, Yongxin; Wang, Cong; Sun, Ying; Ning, Yuping; Liu, Yingfang; Xue, Yafei; Wang, Wenwen; Zhao, Shuxi; Tomasella, Eric; Bousquet, Angélique
• Is Part Of: Solar energy. Volume 119(2015)
• Page Start: 18
• Page End: 28
• Publication Date: 2015-09
• Subjects: Solar selective absorbing coating -- Magnetron sputtering -- Si doping -- Thermal stability; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2015.06.021
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: The work focuses on improving thermal stability of Al/NbTiN/NbTiON/SiO2 coating. Si increases the onset oxidation temperature of NbTiSiN and NbTiSiON layer. Si additions improve the oxidation resistance of the coating at 500 °C in air. The improved coating is stable up to 550 °C in vacuum for 100 h. Abstract: In this work, the NbTiSiN and NbTiSiON layers are used instead of NbTiN and NbTiON layers to further improve the thermal stability of Al/NbTiN/NbTiON/SiO2 multilayer solar selective absorbing coating. The thermal stability of Si-doped individual layers and multilayer coatings are investigated. The X-ray diffraction (XRD) results show that Si incorporation into NbTiN (NbTiSiN) layer does not change its preferred orientation, and the Si-doped NbTiON (NbTiSiON) layer remains in amorphous phase. On the other hand, by introducing Si into NbTiN and NbTiON layers induce significant improvement of the oxidation resistance at 500 °C in air. After ageing in air at 500 °C for 2 h, the absorptance and emittance (at 400 °C) of Al/NbTiN/NbTiON/SiO2 and Al/NbTiSiN/NbTiSiON/SiO2 multilayer coatings change from 0.934/0.13 and 0.931/0.12 to 0.538/0.14 and 0.922/0.13, respectively. Meanwhile the surface roughness increases from 18.3 and 7.9 to 41.5 and 14.7 respectively, as atomic force microscopy (AFM) shows. The Al/NbTiSiN/NbTiSiON/SiO2 coating still has a high absorptance (0.910) and low emittance (0.13, at 400 °C) after ageing at 550 °C in vacuum for 100 h. It displays that Si-doping play an important role in the improvement of the thermal stability.