پديد آورنده :
غافري، زهرا
عنوان :
ايجاد پوشش هاي نانو كريستالي كبالت- تنگستن رسوب الكتريكي و ارزيابي خواص آن
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
شناسايي و انتخاب مواد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد
صفحه شمار :
ده،68ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
محمد علي گلعذار،كيوان رئيسي
توصيفگر ها :
امپدانس الكترو شيميايي
تاريخ نمايه سازي :
24/7/89
استاد داور :
احمد ساعتچي،محمد حسين عنايتي
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Electrodeposition of nanocrystalline Co W coatings and evaluation of their properties Zahra Ghaferi z ghaferi@ma iut ac ir April 21 2010 Department of Material Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language Farsi Dr Mohammad Ali Golozar Prof Supervisor E mail golozar@cc iut ac ir Dr Keyvan Raeissi Assoc Prof Supervisor E mail k raeissi@cc iut ac irAbstract In the present study nanocrystalline Co W coatings were deposited on the copper substrate at current 2densities within the range of 2 5 70 mA cm at room temperature The coatings showed goodadhesion to the substrate All coatings were single phase solid solution It means that coatings weresuper saturation solid solution At all current densities used the grain size of coatings producedremained almost constant It was seen that with increasing the current density the tungsten content ofcoatings decreased This is probably due to the low diffusion of tungsten ion complexes in thediffusion polarization region These coatings showed spherical nodular stracture By increasing thecurrent density the number of nodules and microcracks increased The coatings produced at highest 2current density used i e 70 mA cm showed the most corrosion resistance This could be due to thelowest exchang current density of water reduction in the present of oxygen on these coatings According to the cyclic polarization these coatings are resistant against pitting corrosion in the presentof ionic chloride EIS results confirmed that the mechanism of tungsten co deposition is changed withapplied current density Tungsten deposition proceeds via the reduction of tungsten oxide oradsorption and concequent reduction of complexes formed in the bulk of solution At current densityin the activation polarization region the reduction of tungsten oxide by adsorbed hydrogen wasdominated By increasing the current densities in to the regions of mixed and diffusion polarization the adsorption and reduction of tungsten containing ion complexes would be the controlling parameter As it was observed compared with tungsten content the effect of grain size on the microhardness ofcoatings was negligible the highest microhardness value of about 640 vickers belonged to the 2coatings produced at 2 5 mA cm At this current density the coatings produced had the maximumtungsten content and showed the most wear resistance Key words coating Co W electrodeposition nanocrystalline
استاد راهنما :
محمد علي گلعذار،كيوان رئيسي
استاد داور :
احمد ساعتچي،محمد حسين عنايتي
