Electrochemical deposition of Ni-Fe alloys into porous alumina for solar selective absorbers.

The morphological, structural and optical characterizations of Al/Al 2 O 3 /Ni-Fe cermet solar absorbers have been investigated. The X-ray diffraction patterns indicated the presence of Ni-Fe alloys with variable composition. However, the formation of Ni-Fe amorphous phases was detected for compositions as high as 73% of Fe. X-ray photoelectron spectroscopy measurements revealed the presence of superficial binary and ternary oxides such as NiO, Fe 2 O 3 , and NiFe 2 O 4 . Furthermore, the properties of solar absorptance and thermal emittance were calculated for the cermets. It was found that the presence of Fe decreased the solar absorptance of the cermets up to 5% and decreased the emittance up to 10%. However, an excessive content of Fe increases the emittance ∼5%. Finally, it was demonstrated that cermets containing Ni-Fe alloys can be useful to enhance the optical and spectral selectivity properties of solar absorbers. [ABSTRACT FROM AUTHOR]