4883

4587

كارشناسي ارشد

خوردگي و محافظت ازمواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1388

ده،81ص.: مصور،جدول، عكس،مودار

ص.ع.به فارسي و انگليسي

محمدعلي گلعذار، كيوان رئيسي

محمد حسين فتحي

9/10/88

احمد ساعتچي، رحمت اله عمادي

مهندسي مواد

ID4587

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Electrodeposition of nanostructured zirconia film on AISI 316L stainless steel and its corrosion resistance behaviour Elham Setare Star31@ma iut ac ir July 4 2009 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan IranDegree M Sc Language FarsiProf Mohammad Ali Golozar Supervisor E mail golozar@cc iut ac irAssoc Prof Keyvan Raeissi Supervisor E mail k raeissi@cc iut ac irAssoc Prof Mohammad Hossein Fathi Advisor E mail fathi@cc iut ac irAbstractThin film of zirconia ZrO2 was prepared onto mechanically polished and electrochemicallyprepared surfaces of 316L stainless steel by direct and pulse current Electrodeposition processwas performed at ambient temperature Current density used was 1 7 mA cm 2 After that theelectrodeposits were annealed at 400 C for 2h X ray diffraction patterns obtained indicated thatthe ZrO2 coatings were nanocrystaline with a tetragonal crystallographic structure Grain size ofthe coatings determined by Sherier equation were 19 and 9 nanometer for direct and pulsecurrent respectively Scanning electron microscopy investigation showed that the surfacepreparation have no significant effect on the morphology of coatings However the nature ofcurrent i e Ac or Dc has a significant effect on electrodeposition process The coatingsproduced by direct current showed a heterogeneous structure having a crack mud appearance Conversely pulse current produced a more uniform and dense coating with a smaller grain size EDS results indicated that in all conditions ZrO2 coatings cover the entire surface Crosssections of the coatings deposited by pulse current showed a uniform mean thickness of 1 5 Cmon all specimens In order to evaluate the corrosion performance of coatings Tafel and cyclicpolarization tests were performed in 3 5 NaCl solution Results obtained revealed that surfacepreparation has a significant effect on corrosion behavior Coatings produced by pulse currenthad higher corrosion resistance acting as a barrier coating due to its uniform and densemorphology Pulse coatings provided a passive behavior observed on the Tafel polarization plots The ZrO2 coatings produced on electrochemically prepared surfaces showed a very small passiveregion on the anodic Tafel polarization curves This is believed to be due to the effect of surfacepreparation EIS data obtained from ZrO2 coatings showed that pulse coatings can behave as aphysical barrier for corrosion It was observed that the pulse coatings produced on mechanicalpolished substrate could prevent the pitting corrosion Pulse coatings have a good adhesion tosubstrate Key WordsZirconia nanostructure electrodeposition stainless steel corrosion resistance

محمدعلي گلعذار، كيوان رئيسي

محمد حسين فتحي

احمد ساعتچي، رحمت اله عمادي