科研之友
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摘要
The effect of incorporating nanoparticles on the corrosion resistance of epoxy-coated steel in salt contaminated mortars was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. Researchers conducted electrochemical monitoring of the coated steel embedded in mortar over 100 days of immersion in 0.1 M NaOH solutions. The chloride permeability and microstructure of Portland cement mortar with admixed nano-materials (at 1% by weight of cement) were examined using an electromigration test and field emission scanning electron microscopy (FESEM). Electrochemical monitoring showed that nano Fe2O3 improved the corrosion resistance of the coated rebar. The incorporation of a small amount of nano Fe2O3 (1% by total weight of resin and hardener) into the epoxy coating reduced the corrosion current of the epoxy-coated steel in chloride-contaminated mortar (0.3% chloride by weight of cement). After 100 days of immersion, the nanoparticles reduced the corrosion current of epoxy-coated steel by a factor of 6. The FESEM test revealed that admixing of nano-materials not only led to denser cement mortar but also changed the morphology of cement hydration products. The test results of compressive strength showed that nanoparticles increased the strength of cement mortar. The electromigration test showed that the incorporation of nanoparticles improved the chloride penetration resistance of the mortar, as indicated by the reduced apparent diffusion coefficients of the chloride anion. When nano-SiO2 and nano-Fe2O3 were admixed into fresh cement mortar at 1% by weight of cement, the value of DCl-was decreased by 83%, from 7.35x10(-11) m(2)/s (control specimen) to 1.21x10(-11) m(2)/s and 1.36x10(-11) m(2)/s, respectively.
- 出版日期2017-1
