Nano Tio <sub> 2 </ Sub> Coating And Its Resistance To Marine Corrosion

Nano-titanium dioxide was developed successfully in eighty years 20th. Since imperceptibility of the particle size of titanium dioxide, it had many great merits such as excellent surface properties, particle properties, tremendous chemistry active and surface energy, and great anti-corrosion of heat and chemistry. People all over the word almostly focus on the antibacterial ,antipollution and photic catalyzer, but less research its corrosion behavior and corrosion mechanism in marine. It is important for the continuable development of marine economy to work over the corrosion properties of titanium dioxide in marine environmentIn this article , the nano- titanium dioxide powders were processed through calcining and grinding, in order to got the titanium dioxide particles which have good fluidity and were in 30-150um in size. The titanium dioxide coating on metal material surface was prepared by nowadays commonly used heat spraying technology -Air Plasma Spraying ,having approximately 100um thickness .Through XRD, SEM ,The paper analyzed the ingredient change, surface images of the titanium dioxide coating .By analyzing the plasma spraying principle ,the microstructure of the coating was further discussed.5 cyclical sea simulation tests were done in order to test the average corrosion rate of the titanium dioxide coating suspended in the sea different area belt such as gas zone, splash zone, tide zone, immersion zone, and to analyze the change tendency of the coating corrosion in each zone. In contrast to the blank parallel test specimen, the corrosion resistance of the titanium dioxide coating was definitely shown, further discussing the influencing factorThe electrochemistry impedance technology (EIS) was investigated to test the titanium dioxide coating exposed to the sea for the different time, detailedly studying the changing of the EIS spectrum of coating corroded along with time. The research indicated that, the coating polarization resistance drop quickly in the initial corrosion period, then subsequently has a rise because of the corrosion product and filths blocking the corrosion channel , and tend to stable. A appropriate equivalent circuit was established to analyze the impedance spectrum, inspecting the changing of various parts parameter, further analyzing the coating corrosion process. The research also showed that, the resistance value of titanium dioxide coating with the treatment porous sealing is much higher than that of titanium dioxide coating without the treatment porous sealing, about 1.5 ～2 magnitudes of the latter. The surface of titanium dioxide coating with the treatment porous sealing which were exposed to seawater for two months is still smooth and clear. This indicated that sealing the pores effectively encumber the corrosive medium to penetrate the coating , enhancing the coating corrosion resistance; that Ecorr of the former is more positive fartherly improve the anti-corrosion of the coating.