Structural, optical, and mechanical properties of cobalt copper oxide coatings synthesized from low concentrations of sol-gel process
Amri, A., Jiang, Z-T, Yin, C-Y, Fadli, A., Rahman, M.M., Bahri, S., Widjaja, H., Mondinos, N., Herawan, T., Munir, M.M. and Priyotomo, G. (2016) Structural, optical, and mechanical properties of cobalt copper oxide coatings synthesized from low concentrations of sol-gel process. Physica Status Solidi (a) . Early View.
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Thin films of CoxCuyOz have been coated on aluminum substrates via sol–gel route using low concentration of copper and cobalt precursors at annealing temperatures in range of 500–650 °C. The coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrophotometry, and nanoindentation. The XRD analysis in 2θ-range of 30°–42° revealed that the coatings exhibited low crystallinity of CoCu2O3, CoCuO2, and CuCoO2. The surface bonding structure analyzed using XPS indicated that the coating contained: Cu (tetrahedral Cu+ and octahedral Cu2+), Co (octahedral Co3+, tetrahedral Co2+, and mixed Co2+ and Co3+), and O (lattice, surface, and sub-surface oxygens).
The optical properties characterized using UV-Vis-NIR showed that the reflectance spectra of coatings formed a spectrally solar selective absorber profile associated with the interference peaks and the absorption edges around wavelengths of below 1.2 μm. The maximum absorptance (α = 75.8%) was shown by coating synthesized at 500 °C. The mechanical properties of coatings showed that the increase of annealing temperature increased the coating's hardness (H) and the elastic modulus (E) due to the enhancement of the [CoCuO2/CuCoO2]:[CoCu2O3] oxide phases ratio, as the result, an excellent stability of the wear resistance (H/E) of around ∼0.035 was recorded.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Engineering and Information Technology|
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