Study Of Anticorrosion Mechanism And Application Of TiO₂Thin Films On Stainless Steel

There is the corrosion phenomenon of metal materials which leads to large amountsconsumption of the raw materials, and also loss the function of metal material. Here TiO2thinfilms was coated on the surface of304SS to solve the problem of corrosion phenomenon, andresearch the anticorrosion properties on metal materials. TiO2thin films can have doubleprotection to304SS. On the one hand, TiO2can form a dense film on304SS, prevent metal fromdirect contact with the corrosive medium. On the other hand, TiO2thin films can produceelectrons and holes under UV irradiation, photogengrated electrons arrive to the surface of304SS through external circuit, reduce the corrosion potential of304SS and slow down thecorrosion process, play the role as cathodic protection.In this thesis, we use magnetron sputtering method and sol-gel method to prepare TiO2thinfilms. XRD and SEM was used to character the crastal and surface morphology of TiO2thinfilms, also study the effect of temperature treatment on crystal stricter and grain. Character theeffect of temperature treatment on band gap of. by UV-visible diffuse reflectance. Study theeffect of film thickness and temperature treat on the corrosion resistance of TiO2.The orthogonal design method was used to design magnetron sputtering experiment. Byintuitive and variance analysis of anticorrosion experiment data, concluded the best experimentalconditions. In this preparation condition, the corrosion current density icorrof TiO2-304SS is2.30×10-8A/cm2in dark, and the the negative shift of corrosion potential is214mV in UV light.The TiO2thin films which was prepared by sol-gel method has also been studied. The resultsshowed that in dark condition, the corrosion current density icorris9.88×10-9A/cm2,the thenegative shift of corrosion potential is189mV in UV light. Compared the TiO2thin films, theTiO2has lower corrosion current density in dark was prepared by sol-gel method; but the TiO2has lower potential in UV light was prepared by sol-gel method magnetron sputtering method.In order to improve the anticorrosion effect, TiO2thin films was modified by doping Fe andN elements. The results showed that TiO2thin films modified by doping Fe ions decreased both the energy gap and recombination rate of photo-generated electron-hole pairs. In UV lightcondition,1.0%Fe-TiO2-304SS gets better anticorrosion performance, the negative shift potentialis228mV. The N doped and co-doped TiO2has an energy gap between2.198eV and2.560eV,which can excitation electron-hole pairs in visible light. The N doped TiO2(1N-TiO2-304SS) hasa corrosion potential of-350mV, the negative shift potential is258mV, in visible light condition.The Fe、N co-doped TiO2thin films gets the corrosion potential of-490mV and-350mV, andthe negative shift is360mV and230mV, in UV light and visible light condition, respectively.In conclusion, TiO2thin films is able to achieve the anticorrosion effect to304SS, both inUV light and dark condition. By doping TiO2thin films with different elements, the anticorrosioncondition of TiO2-304SS broadened optical excitation range.from ultraviolet to visible light,expanded the use of spectral range.This thesis also used the results of anticorrosion of TiO2thin films to prevent the stainlesssteel scalpel from corrosion. All of these are more available for a wider using of TiO2thin filmson metal material.