Investigating corrosion protection properties of epoxy thermal insulators through cyclic corrosion test

For preparing epoxy based thermal insulations three types of hollow glass microspheres with different particle sizes 70, 115, and 170 μm were used. Thermal conductivity of coatings in the absence and presence of hollow spheres were evaluated. Thermal conductivity of microsphere containing insulations was found to be much less than epoxy coatings. Hollow spheres with 170 μm diameter showed better insulating properties. Epoxy thermal insulations were exposed to accelerated cyclic corrosion test conditions, and then corrosion resistance reduction of coatings was evaluated by electrochemical impedance spectroscopy. Results showed that microspheres can not only improve insulating properties but also raising corrosion protection features of epoxy coating during 37 days of exposure to cyclic corrosion conditions. Impedance modulus at low frequency (0.01 Hz) of 170 μm hollow sphere containing epoxy coatings were 1.10 and 530 ohm cm2 after 37 days, respectively.