6345

5933

كارشناسي ارشد

خوردگي و حفاظت از مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1390

دوازده،81ص.: مصور،جدول،نمودار

ص.ع.به فرسي و انگليسي

محمدعلي گلعذار،كيوان رئيسي

23/8/90

احمد ساعتچي، محمد حسين فتحي

مهندسي مواد

ID5933

به فارسي وانگليسي: قابل رويت در نسخه ديجيتالي

Corrosion barrier performance of Amorphous Nano crystalline ZrO2 coatings produced on S S by electro deposition Fereshteh Samiee f samiee@ma iut ac ir Department of Materials Engineering IsfahanUniversity of Technology84156 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 irAbstractZirconia ZrO2 coatings were prepared by heat treating the electrodeposited zirconiumhydroxide produced by pulse current on 316L stainless steel The results showed that acoating with amorphous structure is obtained after heat treating at 200oC which reveals nocorrosion barrier performance X ray diffraction patterns obtained indicated thatheattreating at 400oC resulted in ZrO2 coating with nanocrystalline amorphous structure whichreveals a strong corrosion barrier performance As the temperature was raised to 600oC anentirely nanocrystalline tetragonal structure was found for the ZrO2 coating Crestallinesize of the coatings determined by Sherier equation were 9 and 25 nanometer for zirconiacoating heat treated at 400 and 600 C respectively TEM investigation of ZrO2 coatingobtained at 600 C shows that by increasing the heat treatment temperature a completenanocrystalline phase of ZrO2 with an average size of about 30 nm is achieved Scanningelectron microscopy investigation showed that the heat treatment of the coatingshadasignificant effect on the morphology of coatings No cracks were found during the heattreatment of deposits at 200 C The coatings showed no corrosion barrier performancebecause of incomplete dehydration of zirconium hydroxide at this temperature The coatingheat treated at 600 C revealed muddy shape cracks with inferior corrosion barrierperformance Furthermore EIS data obtained from ZrO2 coatings revealed that a very highvalue of pore resistance and Warburg impedance which indicating the diffusion controllednature of corrosion reactions were observed for 400 C heat treated ZrO2 coatings Theimproved mechanical properties including higher nanohardness and higher elasticmodulus were observed for 400 and 600 Cheat treated zirconia coating Nanoindentationresults of ZrO2 coatings produced by heat treating at 600oC showed an increase inmechanical properties such as the hardness and elastic modulus This can be attributed tothe crystallization of ZrO2 and development of tetragonal phase in the coatings Key WordsZirconia nanostructure electrodeposition stainless steel corrosion resistance

محمدعلي گلعذار،كيوان رئيسي

احمد ساعتچي، محمد حسين فتحي