Effect of Electrolyte Composition on the Structure and Properties of Micro-Arc Oxidation Porous Coatings on TA2 Pure Titanium

In order to investigate the effect of porosity on the comprehensive performance of bioactive coatings， a TiO2 coating was prepared on the surface of TA2 pure titanium using micro-arc oxidation.By varying the concentrations of Na2B4O7 and NaOH in the electrolyte， the effects of electrolyte composition on the phase composition， microstructure， hardness， thickness and hydrophilicity of the micro-arc oxidation coating were examined under constant current mode.Results showed that the coating phase was primarily rutile TiO2.The phase composition， morphology， thickness， hardness and wear resistance of the coating were significantly affected by the concentrations of sodium hydroxide and sodium tetraborate.Moderate addition of NaOH can enhance the thickness， porosity， hardness， wear resistance and corrosion resistance of the coating.However， when the concentration of sodium hydroxide was too high， porosity decreased and coating performance was reduced.When the electrolyte formula was 0.15 mol/L NaOH and 0.10 mol/L Na2