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The Microstructure And Corrosion Properties Of Co-10Mn Coating Prepared By Electro Spark Deposition And Micro Arc Oxidation Film On MB8Magnesium Alloy

Posted on:2015-05-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z S QinFull Text:PDF
GTID:2181330422988553Subject:Materials engineering
Abstract/Summary:PDF Full Text Request
Metal connection is one of the key components of the solid oxide fuel cell (SOFC)body,has a very important role。In SOFC long run and in the process of thermal cycling,oxidation of the metal material is almost inevitable。oxidation production is easy toproduce crack and spalling。In addition,the rich Cr oxidation product is easy to produce Crvolatilization, volatile state of Cr easily in cathodic deposition and react with cathodematerials to poison cathode, Reduce the performance of cell stack attenuation rapidly。Thekey to solve this kind of problem is exert protective coating on metal surface。This articleuses electric spark deposition technique in Co-10Mn coatings on304stainless steelsubstrates, and study the morphology of the coating were analyzed, high temperatureoxidation resistance and electric conductivity。Coating morphology results scanningelectron microscope (SEM),surface density is splashing, single point surrounding lungmorphology for the center sag of splash, with a small amount of corrosion pit。XRD testshows that the preparation of coating including matrix and manganese cobalt spinel phase,this is due to the high temperature to melt,the electrodes and the substrates materials bothpermeable formation。Surface specific resistance test showed that compare with pureCo coatings and substrate oxidation surface surface specific resistance of Co-10Mncoating after surface oxidation is smaller。Indicate that the conductivity performance ofCo-10Mn coating on the oxidation process is better。The high temperature oxidation in airweight gain experiment showed that oxidant resistance properties of Co-10Mn coatingis better than that of pure Co coating。This paper introduces the technology of micro arc oxidation protection of magnesiumalloy later, focusing on the influence of voltage on the corrosion resistance of micro arcoxidation coating。The main research under different voltage, current density and time, therelationship between the cathodic polarization curves, impedance coating conductivitymaps and under different voltage on the morphology and structure。From scanning electronmicroscopy (SEM) can be seen, micro arc anodic oxide film is all porous structure。By theXRD analysis of the main components of micro arc oxidation film know for MagnesiumOxide. In the current density and the time of the experiment, different voltage, currenttrends are almost the same。Potent dynamic polarization curves indicated that the preparedfilm corrosion potential increased significantly, magnesium alloy and the corrosion currentdensity was lower than that of the untreated decreased about3orders of magnitude;impedance spectra show that the magnesium alloy matrix and the film showed a singlecapacitive arc, indicate that the process by electrochemical reaction steps of control, and inthe different solution there are different optimal voltage value which makes the bestcorrosion resistance of micro arc oxidation。...
Keywords/Search Tags:electro spark deposition, ASR (area specific resistance), High temperatureperformance, micro arc oxidation, electrochemical method, Corrosion resistance
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