Study on fabricating epoxy coatings reinforced with iron oxide flakes and nano silica

Flake micaceous iron oxide (MIO) pigment is a natural flake pigment, together with nano silica (NS) used to increase mechanical properties and corrosion resistance of coatings based on epoxy resin Epotec YD011X75 cured with Domide G5022. MIO and NS were dispersed into epoxy resin Epotec YD011X75 by mechanical stirring combined with ultrasonic vibration. The structural morphology of the materials was characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Transmission Electron Microscopy (TEM). Functional groups in epoxy/curing agent/MIO polymers analyzed using Fourier Transform Infrared Spectroscopy (FTIR). The thermal property of the material is evaluated by Thermogravimetric and Differential Scanning Calorimetry (TG-DSC). Epoxy coatings with flake micaceous oxide iron, nano silica, phosphate zinc pigment (P), talc filler powder (T), additives, and solvents are prepared by grinding and mechanical stirring. The mechanical properties of epoxy coatings were evaluated by standards for epoxy coatings. The anti-corrosion properties of the coatings on steel were evaluated by the salt fog spray method and electrochemical method. The research results have fabricated two formulations of epoxy coatings based on epoxy resin Epotec YD011X75 with the most appropriate mass ratio of YD011X75/(MIO/P/T) is 40/60 (wt/wt); of which one does not have nano silica (epoxy coating MIO2); one with 1 wt% nano silica (epoxy coating MIO5). The thermal stability of epoxy coating MIO5 is better than epoxy coating MIO2. The decomposition temperature of 50 wt% of epoxy coatings MIO5 and MIO2 is 528.34°C and 470.53°C. The formed epoxy coatings achieve the physical chemistry properties, mechanical properties, and corrosion resistance properties of steel for epoxy coatings, in which the epoxy coating MIO5 is better than the epoxy coating MIO2.