8632

8013

كارشناسي ارشد

استخراج فلزات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1392

سيزده،78ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

علي سعيدي، مهدي احمديان

كيوان رئيسي

21/12/92

محمدعلي گلعذار، حسين ادريس

مهندسي مواد

ID8013

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

79 Isfahan University of Technology Department of Materials Engineering Synthesize and Characterization of Nanocrystalline Nickel Cobalt Alloy by Direct and Pulse Current Electrochemical Deposition Morteza Salehi morteza salehi@ma iut ac ir Date of submission 17 December 2013 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Co Supervisors Dr Ali Saidi a saidi@cc iut ac ir Dr Mahdi Ahmadian ahmadian@cc iut ac ir Abstract Magnetic alloys are a type of engineering materials which are widely used in various industriessuch as computers aerospace and electronics Among these alloys Ni Co alloys were of particularinterest In this study Ni Co nanocrystalline alloys were prepared by electrochemical depositionmethod direct and pulse current and the effect of current density and electrolyte pH when director pulse current were used on the properties of the obtained deposition was investigated The resultof EDS tests have shown that by increasing current density from 70 to 115 mA cm2 the Cobaltcontent in deposited alloys is decreased from 70 to 48 wt in pH 4 and 70 to 50 wt in pH 1 5 but always the ratio of Cobalt to Nickel in the alloy is higher than that in the electrolyte This is dueto the anomalous simultaneous deposition of Ni Co In constant current density by decreasing pHfrom 4 to 2 the Co content of the alloy is decreased from 70 to 42 wt however by furtherdecreasing of pH to 1 5 a 70 wt increase in Co content was observed By applying pulse currentand by changing the pulse off time from 50 to 150 s Co in alloys was increased from 69 wt to 76 wt and with further increase in the pulse off time Co content fell sharply to 41 wt TheX ray patterns indicated that Ni Co alloys are solid solution in the whole range of theircomposition By controlling of the pH and current mode direct or pulse single phase structure fcc and two phase structures fcc hcp can be obtained So that in pH 1 5 at direct current or inpH 1 5 4 at pulse current process just single phase structure fcc was obtained The grain size ofdeposited alloys in direct and pulse current were 24 58 and 15 24 nm respectively Studies on themagnetic properties of prepared alloys using AGFM analysis have shown that by increasing theCobalt content in the alloy and also creating single phase structure fcc magnetic saturation isincreased However the coercivity of the synthesized alloys was determined at about 40Oe So thesynthesized alloys can be categorized as soft magnetic materials Keywords Electrochemical deposition Nickel Cobalt alloys Nanostructures Soft magneticmaterials

علي سعيدي، مهدي احمديان

كيوان رئيسي

محمدعلي گلعذار، حسين ادريس