Effects of the LMVF and HMVF absorption layer thickness and metal volume fraction on optical properties of the MoSi_2-Al_2O_3 solar selective absorbing coating

摘要

A novel MoSi_2-Al_2O_3 solar selective absorbing coating deposited on stainless steel (SS) substrate by magnetron sputtering is reported. The effects of the HMVF and LMVF absorption layers thickness and metal volume fraction on optical properties of the coatings are investigated. As the thickness or metal volume fraction of the HMVF or LMVF layers increases, it is found that the absorptance first increases and then decreases, this can be explained by the regularly changes of the reflectance spectrum. The position of the cutoff limit has a redshift as the thickness of the HMVF or LMVF layers or the metal volume fraction of the HMVF layer increases, which will induce the quick increase of the emittance with temperature. The cutoff limit is almost unchanged as the metal volume fraction of the LMVF layer increases. Most of the experimental results are consistent with the simulated results in the trends.