The Research On Ceramic Membrane Of Magnesium Alloy Was Prepared By Sol Coating And MAO

Micro-arc oxidation technology is the most promising surface treatmenttechnology in recent years, metal’s wear resistance, corrosion resistance, mechanicalstrength and electrical insulation were improved greately after the process.In this thesis,using sol-gel method and micro-arc oxidation technology made the excellent propertiescomposite ceramic membrane of magnesium alloy.Using organic alcohol saline solution prepared SiO₂sol in this thesis. The bestproportion of SiO₂sol-gel was determined through changing the ratio of water andTEOS. The curves of silver sol viscosity varies with aging time showed that it isbenefited to films from24hours to40hours. Sol group into key was analyseed by IRtest, Sol powder had a large amount of Si-O-Si key telescopic vibration absorptionpeaks in l085infrared waves near, which showed that SiO₂colloidal particle had beenformed.Uv absorption spectra showed that SiO₂colloidal particle had characterizationout nanoparticle characteristics.The silver sol was prepared by chemical reduction method, which was dark brown.The silver sol uv absorption spectra showed that: Sol absorption peaks are between330nm-500nm, and it was testified that the nanometer silver exsits in the silver sol bycomparing them with nano silver absorption peaks.The silver sol was dried, and theresults showed that the silver sol powder had Ag and Ag2O according to X-raydiffraction analysis. Viscosity tests showed that the silver sol was stable.Coating SiO₂sol in the MAO, and obtained the composite membrane layer by thesecond micro-arc oxidation. SEM test results showed that the holes and crackthe ofmembrane were almost saw,contained Si quantity significantly greater than MAO.Electrochemical analysis andcorrosion of weightlessness results showed that thecorrosion resistant effect of composite film was better than MAO, Corrosion potentialmoved0.07V for forward direction, Corrosion current density reduced a one order ofmagnitude relative to MAO; Corrosion weightlessness rate from0.1258mg/cm²h to 0.0477mg/cm²h.Coating Ag sol in the MAO, and obtained the composite membrane layer by thesecond micro-arc oxidation.SEM test results showed that membrane changed moredense, pore ratio decreased; composite membrane layer contained Ag elements;XRDtest results showed that the silver compounds produced in the membrane.Weightlessness and electrochemical corrosion tests showed that Corrosionweightlessness rate from0.1258mg/cm²h to0.0736mg/cm²h,and Corrosion potentialmoved0.04V for forward direction, Corrosion current density reduced a half relative toMAO. Friction and wear testing showed the wear resistance of composite membranelayer had been improved greately.