Details

Autor(en) / Beteiligte

• VINCE, J
• VUK, A. Surca
• KRASOVEC, U. Opara
• OREL, B
• KÖHL, M
• HECK, M

Titel

Solar absorber coatings based on CoCuMnOx spinels prepared via the sol-gel process: structural and optical properties

Ist Teil von

• Solar energy materials and solar cells, 2003-09, Vol.79 (3), p.313-330

Ort / Verlag

Amsterdam: Elsevier

Erscheinungsjahr

2003

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Titanium-doped and undoped CuCoMnO,, spinel films were deposited on Al substrates from sols which were made from the following: co-acetate, cu- chloride and Mn-acetate (Ti:CoCuMnOx-I); and Co-acetate, Cu-nitrate and Mn- acetate (CoCuMnOx). The precursors' ratio Co:Cu:Mn was equal to 1:3:3. The solar absorptance (*as) and the thermal emittance (*eT) of the films, which were annealed at 450DGC for 15 or 30 min, were determined from the corresponding diffuse reflectance spectra in the 0.32-20 mum range. The results show that the CoCuMnOx-II films with SiOx protective over-coatings exhibited values of *a = 0.85-0.91 and *eT- below 0.036 after just a single dipping/annealing cycle. The structure of the films was studied with X- ray diffraction (XRD), infrared (IR) absorbance and near-grazing incidence angle (NGIA) reflection-absorption spectroscopy. Our results suggested that the films have a spinel structure with the composition CoCuMnOx. The stability of the films was tested by soaking them in boiling water for 2 h. NGIA IR spectra of the treated films confirmed the formation of the hydrated mixed oxide (Mn-, Co-, Cu-) phases. To improve the stability of the films two kinds of protective over-coatings were tested: one over-coating was based on polysiloxane resin and the other on high-density silica (T-resin). Films that were resistant to boiling water were obtained by applying the high-density silica protective over-coating, which was cured at 140 DGC for 30 min.