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International Journal of Photoenergy
Volume 2014, Article ID 834128, 7 pages
http://dx.doi.org/10.1155/2014/834128
Research Article

Optical and Structural Characterization of Nickel Coatings for Solar Collector Receivers

1Dipartimento di Ingegneria Industriale, Università degli Studi di Firenze, Via di S. Marta 3, 50139 Florence, Italy
2CNR-INO National Institute of Optics, Largo E. Fermi 6, 50125 Firenze, Italy

Received 27 March 2014; Accepted 3 August 2014; Published 21 August 2014

Academic Editor: Ugo Mazzucato

Copyright © 2014 Stefano Pratesi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The development of spectrally selective materials is gaining an increasing role in solar thermal technology. The ideal spectrally selective solar absorber requires high absorbance at the solar spectrum wavelengths and low emittance at the wavelengths of thermal spectrum. Selective coating represents a promising route to improve the receiver efficiency for parabolic trough collectors (PTCs). In this work, we describe an intermediate step in the fabrication of black-chrome based solar absorbers, namely, the fabrication and characterization of nickel coatings on stainless steel substrates. Microstructural characteristics of nickel surfaces are known to favorably affect further black chrome deposition. Moreover, the high reflectivity of nickel in the thermal infrared wavelength region can be advantageously exploited for reducing thermal emission losses. Thus, this report investigates structural features and optical properties of the nickel surfaces, correlating them to coating thickness and deposition process, in the perspective to assess optimal conditions for solar absorber applications.