5 research outputs found
Synthesis and characterization of silver-rich coatings loaded with functionalized clay nanoparticles
Hybrid solâgel coatings for corrosion protection of galvanized steel in simulated concrete pore solution
The aim of this experimental research was to study the electrochemical behavior of organicâ
inorganic hybrid (OIH) coatings for corrosion protection of hot-dip galvanized steel (HDGS) in the first
instants of immersion in simulated concrete pore solution (SCPS) (pH > 12.5). The electrochemical
performance of the OIH coatings was assessed by electrochemical impedance spectroscopy, potentiodynamic
polarization curves, macrocell current density, and polarization resistance. The OIH coatings were
prepared via the solâgel method and were deposited on HDGS surfaces by dip-coating using one or three dip
steps. The electrochemical results obtained for HDGS samples coated with OIH matrices in SCPS showed
higher corrosion resistance than bare HDGS; as the molecular weight (MW) of Jeffamine increased the
barrier protection of the coating decreased. The lowest protection efficiency was found for HDGS samples
synthesized with oligopolymers with an MW of 2000.
Coatings produced with an oligopolymer of 230 MW
conferred the highest protection. The surface morphology
of the OIH coatings deposited on HDGS
surfaces was studied by atomic force microscopy. The
results show that the roughness of the OIH films
depends on the MW of Jeffamine and on the number
of dip-coating steps used. Thermogravimetry results
show that the Jeffamine MW affected the thermal
properties of the prepared OIH samples. The prepared
OIH materials are thermally stable within the range of
20â80 C.The authors would like to gratefully acknowledge the financial support from Fundacao para a Ciencia e Tecnologia (FCT) for the PhD grant SFRH/BD/62601/2009 and EU COST action MP1202: HINT-"Rational design of hybrid organic-inorganic interfaces: the next step towards functional materials.''info:eu-repo/semantics/publishedVersio
Organic-inorganic hybrid sol-gelcoatings for metal corrosion protection: a review of recent progress
This paper is a review of the most recent and relevant achievements (from 2001 to 2013) on the development of organicâinorganic hybrid (OIH) coatings produced by solâgel-derivedmethods to improve resistance to oxidation/corrosion of different metallic substrates and their alloys. This review is focused on the research of OIH coatings based on siloxanes using the solâgel process conducted at an academic level and aims to summarize the materials developed and identify perspectives for further research. The fundamentals of solâgel are described, including OIH classification, the interaction with the substrate, their advantages, and limitations. The main precursors used in the synthesis ofOIHsolâgel coatings for corrosion protection are also discussed, according to the metallic substrate used. Finally, a multilayer system to improve the resistance to corrosion is proposed, based on OIH coatings produced by the solâgel process, and the future research challenges are debated.FundacĂŁo para a CiĂȘncia e Tecnologia (FCT) for the PhD grant SFRH/BD/62601/2009, Centro de QuĂmica [project F-COMP-01-01024-FEDER-022716 (ref. Pest-C/Qui/UI0686/2011)-FEDERCOMPETE]
and EU COST action MP1202: HINT - Rational design of hybrid organic-inorganic interfaces:
the next step towards functional material