Interface Bonding and Corrosion Resistance of Alumina-Titania Ceramic-Coated Rebars: A First-Principles and Experimental Study

Corrosion of steel bars embedded in reinforced concrete structures considerably reduces the service life and even causes early failure of the structure. Herein, alumina/titania ceramic coated rebars is investigated in terms of interface bonding and corrosion resistance. By means of first-principles study, the Fe-O interaction at the steel-ceramic interface is probed, illustrating the effect of doped Ti on the thermodynamic stability and interface bonding of Fe/Al2O3 interface. Experimentally, the phase transition from α-Al2O3 to γ-Al2O3 at high temperature is uncovered, which results in the densification and self-repairing of defect regions of the coating. Doped titania can further diminish coating's porosity and promote the interface bonding, and consequently decay its deterioration after exposure to simulated pore solution. In addition, improving fineness of the precursor can also diminish permeable defects and so exhibits well performance on isolating rebar from electrolyte.