بررسی میکروساختار و رفتار اکسیداسیون و الکتریکی فولاد Crofer 22APU پوشش داده شده با تیتانیوم برای کاربرد در اتصال‌دهنده‌های پیل سوختی اکسید جامد

نویسندگان

1 1. بخش مهندسی دانشکده مهندسی مکانیک و مواد، دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته، کرمان

2 2. بخش مهندسی مواد، دانشکده فنی و مهندسی، دانشگاه شهید باهنر کرمان

چکیده

 یکی از مؤثرترین راه ­ها برای بهبود مقاومت به اکسیداسیون اتصال دهنده­ های مورد استفاده در پیل‌های سوختی اکسید جامد، اعمال یک لایه پوشش رسانای محافظ است. در این پژوهش، فولاد فریتیCrofer 22APU در یک مخلوط پودر پایه تیتانیوم به‌روش سمانتاسیون فشرده پوشش داده شد. ترکیب پودر برای پوشش‌دهی تیتانیوم به صورت20 درصد وزنی Ti، 5 درصد وزنی NH4Cl به‌عنوان فعال‌کننده و 75 درصد وزنی Al2O3 بود. بهینه دما و زمان برای دست­یابی به بهترین کیفیت پوشش از لحاظ چسبندگی و عدم تخلخل 800 درجه سانتی‌گراد به‌مدت زمان هفت ساعت بود. پوشش تیتانایز حاصل شامل فاز­های TiFe، TiFe2 و TiCr2 بود. نتایج مربوط به آزمون­ های اکسیداسیون همدما و اکسیداسیون سیکلی در دمای 900 درجه سانتی‌گراد، نشان داد که نمونه‌های پوشش داده شده با تیتانیوم مقاومت به اکسیداسیون بهتری نسبت به نمونه‌های بدون پوشش دارند. مطالعات ساختاری و فازی نمونه­ های پوشش­ دار و اکسید شده با میکروسکوپ الکترونی روبشی و آزمون پراش پرتو ایکس انجام شد. در طول فرایند اکسیداسیون، پوشش به فازهای TiFe، TiFe2، TiFe2O5، TiO2 و TiCr2O4 تبدیل شده ­است. افزایش وزن نمونه‌های پوشش­ دار نسبت به نمونه‌های بدون پوشش کمتر بود که نشان می‌دهد پوشش به‌طور مؤثری زیرلایه را در برابر اکسیداسیون حفظ می‌کند. همچنین، مقاومت الکتریکی نمونه‌های پوشش­ دار از نمونه‌های بدون پوشش بالاتر بود.

کلیدواژه‌ها

عنوان مقاله [English]

Investigation on the Microstructure, Oxidation and Electrical Behavior of Ti-coated Crofer 22APU Steel for SOFC Interconnect Applications

نویسندگان [English]

  • H. Ebrahimifar 1
  • M. Zandrahimi 2
  • F. Ekhlaspour 2
1 1. Department of Materials Engineering, Faculty of Mechanical and Materials Engineering, Graduate University of Advanced Technology, Kerman, Iran.
2 2. Department of Metallurgy and Materials Science, Shahid Bahonar University of Kerman, Kerman. Iran.
چکیده [English]

One of the most effective ways to improve oxidation resistance of interconnects used in solid oxide fuel cells (SOFCs) is to apply a layer of conductive protective coating. In this study, Crofer 22APU ferritic steel was coated in a titanium- based powder mixture by pack cementation method. The powder composition for titanium coating was Ti 20 wt.%, NH4Cl 5 wt.% (activator) and Al2O3 75 wt.%. The optimum temperature and time to obtain the best coating quality in terms of adhesion and porosity were 800 °C and 7 hours, respectivly. The obtained titanized coating consisted of TiFe, TiFe2 and TiCr2 phases. The results of isothermal and cyclic oxidation tests carried out at 900 °C, showed that titanium-coated samples had better oxidation resistance than non-coated samples. Microstructural and phase studies of coated and oxidized samples were performed by scanning electron macroscopy (SEM) and X-ray diffraction analysis (XRD). During oxidation process, the coating layer was converted into TiFe, TiFe2, TiFe2O5, TiO2 and TiCr2O4 phases. The coated specimens had lower weight gains relative to uncoated samples showing that coating effectively protects the substrate against oxidation. Moreover, coated samples had higher electrical resistance than uncoated ones.

کلیدواژه‌ها [English]

  • Oxidation
  • Titanium
  • Crofer 22APU stainless steel
  • solid oxide fuel cell

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مواد پیشرفته در مهندسی
دوره 38، شماره 3
آذر 1398
صفحه 1-13

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