Development of nickel modified Fe3O4 solar selective coatings for solar absorber applications
Ajoy K. Saha, Rajesh Kumar, Belal Usmani, Laltu Chandra, Ambesh Dixit
Volume 1, Issue 2, Page 140-145, Year 2016 | DOI: 10.5185/amp.2016/205
Keywords: Solar selective coatings, electrochemical deposition, absorptance, emittance, copper substrate.
Abstract: We report the development of Fe 3 O 4 /Cu, and Ni-Fe 3 O 4 /Cu based spectrally selective coatings for solar absorber applications using two different electrochemical baths. The deposition processes were optimized for both electrochemical baths and it was observed that the controlled introduction of nickel in Fe 3 O 4 matrix is important to achieve enhanced solar thermal response. The fabricated coatings were characterized to understand the structural, micro-structural and optical properties, to investigate their phase, chemical composition, surface morphology, thickness and solar thermal properties. Ni-Fe 3 O 4 composite coatings exhibited improved adhesion to Cu substrate and allowed better thickness control when compared to Fe 3 O 4 structures without Ni. Improved substrate adhesion and optimized thickness resulted in better optical properties for these coatings. The optimized Ni-Fe 3 O 4 coatings exhibit maximum spectrally averaged absorptivity (α = 0.87) in the 300 – 900 nm wavelength range, and minimum spectrally averaged emissivity (ε = 0.18) in the 2.5 – 25 μm infrared range at room temperature. For Fe 3 O 4 coatings developed on Cu substrates without Ni, maximum absorptance and minimum emittance values obtained were 0.76 and 0.08 respectively. Ni-Fe 3 O 4 coating thickness was measured ~32 μm. Copyright © 2016 VBRI Press