直流反应溅射沉积Al2O3薄膜及其在SS-AlN金属陶瓷太阳吸收涂层的应用

在沉积不锈钢-氮化铝(SS-AlN)金属陶瓷太阳吸收集热管的磁控溅射三靶镀膜机上,安装了UPS03反应溅射闭环控制单元,实现反应溅射Al2O3稳定反馈控制。采用国产直流电源在Al靶表面处于过渡态下,成功制备了吸收几乎为零的Al2O3薄膜。溅射功率在14kW时,反应溅射沉积Al2O3的靶电压波动可长时间稳定控制在±3 V范围内,沉积速率为5.4 nm/(min·kW),约为Al靶在无反应气体溅射下沉积Al薄膜速率的74%。采用Al2O3代替AlN作为减反射层,应用到SS-AlN太阳选择性吸收涂层中,进一步提高了复合膜的太阳光学性能,太阳吸收比由AlN作为减反射层的0.956提高到0.965,红外发射比不变,仍为0.044。

Reactively Sputtered Al2O3 Coating and Its Applications in Fabrication of Cermet Solar Collector Tubes

The Al2O3 coatings were deposited by DC reactive magnetron sputtering on the outer wall surfaces of the inner tube of the cermet solar collector,coated with Cu,stainless steel and aluminum nitride ceramics layers.Various factors influencing the Al2O3 deposition,such as the sputtering power,pressure,deposition rate,and ratio of the gas flow rates.The results show that the Al2O3 films outperforms AlN films when used as the anti-reflection layer in stainless steel aluminum nitride(SS-AlN) metal ceramic solar absorbing coatings.The solar absorptance of the Al2O3 coatings,grown under optimized conditions,was found to be close to zero,resulting in an absorptance of 0.965,0.009 higher than that of AlN coatings,with no change in the infrared emission rate(0.044).