Abstract:
Corrosion resistant coatings are prepared from a hybrid nanocomposite aerogel derived from tri-functional
silanes, methyltrimethoxysilane (MTMS) and glycidyloxypropyl trimethoxysilane (GPTMS) and from a
zirconium isopropoxide (ZIP) precursor which acts as an inorganic nano-dispersion in an organically
modified silane (ORMOSIL) matrix. A series of hybrid compositions of MTMS and GPTMS are prepared in
which the amount of ZIP is varied. The variations in the pH, viscosity and gelation time of the prepared
compositions are monitored. The wet alcogels thus obtained are homogenized in a solvent using an
ultrasonicator followed by coating the suspension on aluminium alloys and glass substrates using a dip
coating unit. The prepared coatings are further dried and annealed at 400 1C for 1 h. The wet alcogels are
also dried under ambient conditions for seven days resulting in hybrid nanocomposite aerogel monoliths
and are calcined at 400 1C. The hybrid nanocomposites and coatings are further characterized using X-ray
diffraction analysis, Fourier transform infrared spectroscopy, BET surface area analysis, X-ray photoelectron
spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectroscopy,
potentiodynamic polarization and EIS measurements. The hybrid nanocomposite coated aluminium alloy
shows enhanced corrosion protection when compared to the uncoated aluminium alloy. The anticorrosive
feature of the ORMOSIL–ZrO2 hybrid nanocomposite coatings makes them an important candidate in the
field of protective environment resistant coatings.
