Study On Corrosion Resistance Coating By Microarc Oxidation Technique On Titanium Alloy

Titanium and titanium alloys have excellent high strength,biocompatibility and corrosion resistance,and have broad application prospects.Therefore,the surface modification of titanium alloy has attracted people's attention.Microarc oxidation(micro-arc oxidation)of titanium and titanium alloys can produce a porous surface.Ceramic properties combined with matrix solid oxides.The oxide layer has wear resistance,corrosion resistance,and electrical insulation properties compared to titanium alloy substrates.improve.In this study,the micro-arc oxidation(micro-arc oxidation)method was used to prepare the oxide film on the surface of titanium alloy.The corrosion resistance was discussed through chemical etching and electrochemical corrosion.The microarc oxidant was NaAlO2 solution system.The specific microarc oxidation process conditions were: NaAlO2: 16 g / L,additive NaOH(2g / L),and the pH of the solution was controlled at 10-12.Current density is about 5-7a / dm2,power frequency 700hz-800 hz,oxidation time 40 min.The surface morphology and phase composition of the ceramic film were analyzed by field emission scanning electron microscope(FESEM),confocal laser scanning microscope(CLSM)and X-ray diffraction(XRD).The surface roughness of the oxide film was measured with a laser confocal scanning microscope(CLSM).The micro-arc oxidation samples were 1.5%,3.5% and 5% sodium chloride solution,NaOH solution and Na2SO4 and NaCl mixed solution were used for chemical immersion experiment and electrochemical corrosion experiment.The experimental results show that with the increase of the concentration of sodium chloride solution,the corrosion of the film surface is intensified.Through the polarization curve and impedance spectrum,it can be observed that the oxide film layer significantly improves the corrosion resistance of the substrate.