Study On Preparation Of Micro-Arc Oxidation Film On TC4 Alloy With Titanium Dioxide Colloid In Electrolyte

Titanium alloy,as a new type of metal material,has been highly valued in multiple fields both domestically and internationally due to its excellent comprehensive mechanical properties.And it is widely used in medical,aerospace,military,shipbuilding and other fields.However,with the in-depth research on titanium alloys and the continuous development of industry,the problems existing in titanium alloys have also become prominent.Low wear resistance,low surface hardness,and poor corrosion resistance in special environments limit the application and development of titanium alloys.To make up for the shortcomings of titanium alloys,it is necessary to treat their surfaces while maintaining the good plasticity and toughness of the internal metal,in order to meet the requirements of improving surface hardness,wear resistance,corrosion resistance,and other special functions.This article conducts micro arc oxidation treatment on TC4 titanium alloy,and adds different concentrations of nano titanium dioxide colloids,5nm titanium dioxide particles,and 200 nm titanium dioxide particles to the electrolyte.A layer of oxide film is grown on the surface of TC4 titanium alloy to improve the material’s performance.Systematically analyze the effects of three additives on the microstructure and comprehensive performance of the film layer under gradient concentration.In this article,different concentrations of nano titanium dioxide colloids,5nm titanium dioxide particles,and 200 nm titanium dioxide particles were added to the electrolyte to prepare an oxidation film with special properties on the surface of TC4 alloy.The element and phase composition of the film layer were analyzed by X-ray and photoelectron spectroscopy,and the microstructure,three-dimensional morphology,and surface roughness of the film layer were observed using scanning electron microscopy(SEM),energy dispersive spectroscopy,and laser confocal microscopy systems.Test the adhesion ability of the film layer to the substrate using an automatic scratch tester for coating adhesion;Use a wear resistance testing machine to test the wear resistance of the film layer;Using a precision salt spray test chamber to simulate the marine environment for salt spray corrosion of the film layer,and testing its corrosion resistance.Systematically analyze the effect of titanium dioxide additive concentration on micro arc oxidation,and deeply explore the influence of additives on different stages of the micro arc oxidation process.Through research,it has been found that the influence of three types of nano titanium dioxide on the oxidation process is concentrated in the micro arc discharge stage.Both5 nm colloids and particles can form colloids in the electrolyte,but the aggregation phenomenon of 5nm particles is more severe.The 5nm colloid can significantly advance the growth process of the film layer.With the increase of 5nm titanium dioxide colloid content,the discharge phenomenon becomes more and more intense during the micro arc oxidation process,the average current density gradually increases,the film thickness gradually increases,the rutile content in the film increases,and the wear resistance and corrosion resistance of the film improve.The density of the film layer shows a trend of first increasing and then decreasing,and the roughness of the film layer shows a trend of first decreasing and then increasing.When the concentration of titanium dioxide colloid is1.5g/L,the comprehensive performance of the film layer is the best.When the additive is5 nm titanium dioxide particles,it will also increase the current density.The best performance is achieved at a concentration of 1.5g/L,and its overall performance improvement effect is not as significant as that of colloids.However,it can significantly reduce the diameter of micropores in the oxide film.The improvement effect of 200 nm particles on the performance of the film layer is the worst.As the concentration increases,the micropore diameter of the film layer decreases,but the film layer gradually becomes loose and microcracks increase.When the concentration is 3g/L,its comprehensive performance is lower than that of the film layer formed without additives.