No abstract

The surfaces of nanoparticles of SiO 2 , TiO 2 and Al 2 O 3 have been modified by γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH-560) in order to achieve proper dispersion of nanoparticles and possible chemical interactions between nanoparticles and polymeric coatings, and then the homogeneous fluoropolymer coatings containing nanoparticles of SiO 2 , TiO 2 and Al 2 O 3 have been successfully prepared on mild steel substrates. The surface morphologies of the coatings were characterised by field emission scanning electron microscopy. The effects of incorporating various nanoparticles on the corrosion resistance of fluoropolymer-coated steel were investigated by potentiodynamic polarisation curve, electrochemical impedance spectroscopy and salt spray tests. The results showed that KH560-modified nanoparticles can decrease agglomeration effectively, and the nanoparticles play a beneficial role in improving the corrosion resistance of the coated steel significantly. In addition, SiO 2 nanoparticles are of the best effect among three kinds of nanoparticles.

The surfaces of SiO 2 ultra-fine particles with different sizes have been modified by γ-(2, 3epoxypropoxy)propytrimethoxysilane (KH-560) silane coupling agent. Then the homogeneous fluoropolymer/SiO 2 composite coatings have been successfully prepared on mild steel substrates. The surface grafting of KH-560 on SiO 2 particles was detected by means of Fourier transform infrared spectroscopy, thermo gravimetric analysis and transmission electron microscopy. The surface morphologies and corrosion resistance of fluoropolymer/SiO 2 composite coatings were characterised by field emission scanning electron microscopy, potentiodynamic polarisation as well as electrochemical impedance. The results showed that KH-560-modified SiO 2 particles can decrease agglomeration effectively, and the particles play a beneficial role in improving the corrosion resistance of the coated steel significantly. There exists an obvious effect of SiO 2 particles size on the corrosion resistance of fluoropolymer/SiO 2 composite coatings. Also, the SiO 2 particles with diameter of 150 nm are of the best effect among all particle sizes.