6347

5935

كارشناسي ارشد

خوردگي و حفاظت از مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1390

سيزده،74ص.: مصور،جدول،نمودار

ص.ع.به: فارسي و انگليسي

احمد ساعتچي، محمود منير واقفي

محمد ژياني

23/8/90

كيوان رئيسي، ايراهيم حشمت دهكردي

مهندسي مواد

ID5935

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Formation of Nano Ni P Electroless Coating on the Aluminum Alloy Substrate for Bipolar Plates in Proton Exchange Membrane Fuel Cell Amirkhosro Soleimani Email address erfansoly@gmail com Date of submission April 30 2011 Department College of Material Engineering Isfahan University of TechnologyDegree M Sc Language Farsi Supervisior s Name and Email address A Saatchi asaatchi@cc iut ac irS M Moonir vaghefi vagh monir@ma iut ac irAbstractIn this study electroless Ni P coating was deposited on aluminium substrate with and without stabilizers inthe electroless bath After 2 4 and 6 hours deposition thickness of coating with stabilizers were 20 35 and43 microns respectively and thickness of coating without stabilizers were 24 39 and 48 microns Stabilizersdecrease deposition rate with adsorption on coating Also deposition rate in pH 4 is lower than higher pH X ray diffraction analysis showed all of the coatings had semi amorphous structures The structures weremixture of amorphous phase and crystalline phase that contained Ni 111 Electrochemical impedancespectroscopy testing showed after 12 hours immersion of samples in stimulated solution charge transfer 2resistance Rct in samples with 20 35 and 43 microns coating were 13 5 16 5 and 17 k cm and insamples with 24 39 and 48 microns coating were 28 34 and 42 k cm2 respectively This showedcorrosion resistance increased without stabilizers in the bath Also Electrochemical impedance spectroscopytesting on 35 and 39 micron coating showed after 80 days of immersion of samples the solution could notdiffuse through coating and also showed passivation in samples with stabilizers were stronger Tafelpolarization testing showed corrosion rate in coating with stabilizers in samples with 20 35 and 43 micronscoating were 8 5 and 4 A cm2 and in coating without stabilizers in samples with 24 39 and 48 micronscoating were 0 9 0 6 and 0 5 A cm2 that showed corrosion rate decreased one order of magnitude withoutstabilizers in the bath Corrosion potential in coating with stabilizers in samples with 20 35 and 43 micronscoating were 268 259 and 228 mV and in coating without stabilizers in samples with 24 39 and 48microns coating were 360 305 and 305 mV respectively This showed because of deposition of bathimpurities in bath without stabilizers corrosion potential had become more active Potentiostatic testingshowed in cathodic conditions current density in coating with stabilizers was 10 mA cm2 and in coatingwithout stabilizers was 1 mA cm2 Also in anodic condition current density in both of coatings with andwithout stabilizers were the same and about 100 A cm2 Analysis results with WDX showed in coatingwith stabilizers phosphorus content was 9 11 wt and sulfur content was 0 2 0 5 wt Also phosphoruscontent in coatings without stabilizers was 9 12 wt and there was no sulfur in coatings Stabilizers containsulfur element that adsorb in the plating process The reason for increasing corrosion rate could be thepresence of sulfur in the coating Interfacial contact resistance ICR testing showed that before potentiostatic 2corrosion testing ICR in all of samples was about 30 m cm But after corrosion testing ICR increased as 2ICR in coatings with stabilizers was about 160 m cm and in coatings without stabilizers was about 70m cm2 Keywords proton exchange membrane fuel cell bipolar plates Ni P electroless deposition corrosionresistance interfacial contact resistance

احمد ساعتچي، محمود منير واقفي

محمد ژياني

كيوان رئيسي، ايراهيم حشمت دهكردي