Anti-corrosion performance of chemically bonded phosphate ceramic coatings reinforced by nano-TiO2

To promote anti-corrosion property of chemically bonded phosphate ceramic coatings (CBPCs), the nano-TiO 2 is selected as the reinforcement. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS) and the electrochemical analysis are carried out to clarify the role of nano-TiO 2 on the improvement of anti-corrosion performance. The experiments show that with the addition of nano-TiO 2 , the curing temperature and the activation energy of the curing process increase, which allows longest reaction and positively drives curing reactions at elevated conversions. The enhancement of anti-corrosion performance of CBPCs reinforced by nano-TiO 2 particles is based on three main mechanisms. Firstly, more bonded phase (AlPO 4 ) can be formed with the addition of nano-TiO 2 , which can help CBPCs to get more compact microstructure. Additionally, AlPO 4 particles possess the low density and good corrosion resistance , which leads to the increase in the corrosion resistance of CBPCs. Secondly, increasing content of nano-TiO 2 can also strengthen the compactness of CBPCs to protect the substrates from the penetration of aggressive electrolyte and prolong electrolyte diffusion path . Thirdly, through the analysis of microstructure of CBPCs, it is found that most of the hydrophobic nano-TiO 2 particles homogeneously distribute on the surface of CBPCs. Therefore, CBPCs show well hydrophobic performance, which can further improve the anti-corrosion property of themselves.