Premium
Protective organic‐inorganic hybrid coatings on mild steel derived from Ti(OC 4 H 9 ) 4 ‐modified precursors
Author(s) -
Nguyen V.,
Perrin F. X.,
Vernet J. L.
Publication year - 2004
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200303787
Subject(s) - materials science , dielectric spectroscopy , methacrylate , coating , chemical engineering , titanium , capacitance , methacrylic acid , gravimetry , adhesive , electrochemistry , composite material , polymer , metallurgy , chemistry , copolymer , electrode , geotechnical engineering , layer (electronics) , reservoir modeling , engineering
Titania‐poly(methyl methacrylate‐co‐butyl methacrylate‐co‐methacrylic acid) hybrids prepared by a sol‐gel method were deposited by dip coating on mild steel. Transparent and defect free coatings with titania content ranging between 0 and 12.7 wt.% have been prepared. Barrier properties and dry adherence have been tested by electrochemical impedance spectroscopy (EIS) and the vertical pull‐off test, respectively. The pull‐off test results suggest that the titanium alkoxide precursor must intercede on the substrate/coating interphase during film formation to create specific adhesive bondings with the substrate. In this paper, two capacitance models are used to estimate the water uptake, one based on a uniform and one on a heterogeneous distribution of sorbed water. Water uptake determined from these two models is compared to the gravimetry results. It is suggested that a reliable determination of the actual water uptake in coatings from capacitance measurements require an extensive experimental work. The variations in the state of sorbed water with the specimen type or immersion time, the leaching of organics during immersion or the slow diffusion of ions are fundamental factors that must be considered when comparing the water uptake determined from gravimetry and capacitance models.