Study On Titanium Anodizing Behavior And Corrosion Resistance In RGO Electrolyte

Titanium oxide-TiO₂,non-toxic,has a high photocatalytic activity,can degrade organic pollutants,inhibit bacterial growth and reproduction is usually used to prepare antibacterial packaging materials.Titanium spontaneously forms an oxide film that is thin in air,and has poor corrosion resistance and wear-resistance.At present,the surface of titanium metal is usually modified by anodizing process.Commonly used anodizing electrolytes are mainly strong acid and alkali solutions.These electrolytes are volatile,highly toxic and highly dangerous.Therefore,the development of a green and environmentally friendly electrolyte is particularly important.In this paper,a new environmentally friendly reduced graphene oxide?RGO?/citric acid?C6H8O7?system electrolyte was developed.The effects of anodic oxidation potential and oxidation time on the growth,crystallization and corrosion resistance of titanium oxide film was studied.The growth and crystallization mechanism of the oxide film is explored.The study found:The conductivity of the developed RGO/C6H8O7 system electrolyte is 482.5 us/cm.The conductivity of the electrolyte gradually increases with the increase of graphene oxide concentration,reduction time and electrolyte temperature.Raman spectroscopy tests on the anodized film revealed that the titanium oxide compound in the anodized film exists as anatase TiO₂.At a low voltage of 10V.the crystalline absorption peak of TiO₂ can be observed for 20 min.As the oxidation voltage increases,the TiO₂ crystal content in the oxide film gradually increases,however,the oxidation potential has no effect on the crystal type of the oxide film.When the oxidation voltage is 50 V,the anatase TiO₂ has the highest crystalline peak intensity,the best crystallinity,and exhibits the best corrosion resistance.Compared with the matrix sample,its self-corrosion current jcorr is reduced by 93.64%.Polarization resistance Rp and self-corrosion potential Ecorr increased by 93.36%and 60.73%,respectively.The oxidation time has an important influence on the growth and crystallization of the oxide film.Before the growth rate and dissolution rate of the oxide film reach equilibrium,prolonging the oxidation time is beneficial to the formation of anatase TiO₂,but has no effect on the crystal type of the oxide film.Compared with low potential,there is a higher growth rate at high potential.At an oxidation voltage of 50 V,the oxidation time is 5,10,20 and 30 min,respectively.The oxidation time is 20 min.The sample has higher corrosion resistance,the low jcorr is 20.58 nA·cm-2,Ecor and Rp the maximum values are-185.37 mV and 1.821 MQ·cm2,respectively.Compared with Ti samples,jcorr is reduced by 93.64%,and Rp and Ecor are improved by 93.36%and 60.73%,respectively.For the growth and crystallization mechanism of the oxide film,we believe that it is a process of transition from amorphous to crystalline state.The defects on the titanium substrate and the oxide film provide the core for the TiO₂ crystallization,and the temperature gradient between the oxidation interface and the titanium matrix provides the driving force for the crystallization.