Abstracts Book - IMRC 2018

• SC4-P037
ELECTRODEPOSITION OF SELECTIVE COATINGS BASED ON
COBALT-MANGANESE OXIDES FOR THERMOSOLAR
APPLICATIONS
Marco de Jesús Cetina Dorantes 1 , Francisco Iván Lizama Tzec 1 , Dallely Melissa Herrera
Zamora 1 , Gerko Oskam 1
1
CINVESTAV-Mérida, Física Aplicada, Mexico.
Concentrated solar power systems (CSP) use an absorber receiver tube with a
selective coating. The tubes are generally encased in an evacuated glass tube to
protect the selective coating and to minimize losses due to convection and heat
conduction. Selective coatings that can be exposed to air would lower the
current costs of systems that use vacuum, hence, high temperature, air stable
selective coatings are an interesting alternative.
Black oxides of transition metals with spinel structure are prospects as a new
family of selective absorbent materials due to their optical properties and
thermal stability. In addition, precursors of these oxides can be
electrodeposited, opening a window of new possibilities for synthesis and
characterization of these materials.
In this work we report on the optimization of the solar absorptance and thermal
emittance of a ternary oxide based on Co-Mn. Films were deposited
galvanostatically on stainless steel AISI 304 / Ni, and the spinel ternary oxide was
obtained by a thermal treatment at 560 °C for a short time. The electrochemical
behavior of the deposition bath was evaluated using cyclic voltammetry, and a
Hull cell was used to optimize the bath composition, pH, and deposition current
density. The coatings were characterized by reflectance spectra using UV-Vis,
NIR and IR spectrophotometers with integrating spheres. The solar absorptance
was calculated by weighting the reflectance spectrum against the solar radiation
spectrum ASTM G173-03. The thermal emittance was calculated weighting the
reflectance spectra against the black body radiation function at 100 o C. The
morphology of the films was evaluated with scanning electron microscopy, using
Energy Dispersive Spectroscopy to determine the film composition. The
crystalline structure of the films was studied by X-ray diffraction measurements
and the film oxidation in air was studied with thermogravimetric measurement
in the 35 o C - 900 o C range. We conclude that Co-Mn ternary oxides are