1 research outputs found
Coatings produced by electrophoretic deposition from nano-particulate silica sol–gel suspensions
Sol–gel technology allows the production of hybrid coatings on metals using low temperatures for densification, but has an
important limitation related with the maximum coating thickness attainable, typically lower than 2 mm. The incorporation of
nano-particles to the sol can make it possible to increase the coating thickness, without increasing the sintering temperature. This
work deals with the preparation of thick sol–gel coating by electrophoretic deposition (EPD). Commercial SiO2 nanoparticles are
suspended in an acid-catalysed SiO2 sol, whose stability is largely increased by adding tetramethylammonium hydroxide (TMAH)
up to pH 6. Coatings are formed by dipping and by EPD on AISI 304 stainless steel substrates. The protective behaviour against
corrosion in aggressive media (i.e. marine water) of the produced films is studied. EPD leads to coatings as thick as 5 mm with
good corrosion resistance, while the suspension stability is increased by 15 times compared with that of the starting acid
suspension.Peer reviewe