اعمال و مشخصهیابی پوششهای نانوکامپوزیتی YSZ-AL۲O۳ با روش الکتروفورتیک
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[پایاننامه]
Parallel Title Proper
Electrophoretic Deposition and Characterization of YSZ-Al۲O۳ Nanocomposite Coatings
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/مینا نوروزپور
.PUBLICATION, DISTRIBUTION, ETC
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: مهندسی مواد
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، ۱۳۹۷
PHYSICAL DESCRIPTION
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۹۸ص.
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:
GENERAL NOTES
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زبان: فارسی
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چاپی - الکترونیکی
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مصور، جدول
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کارشناسی ارشد
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مهندسی مواد - گرایش نانومواد
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۱۳۹۷/۰۶/۰۱
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صنعتی سهند
SUMMARY OR ABSTRACT
Text of Note
در تحقیق حاضر ریزساختار ,استحکام چسبندگی ,ریزسختی و مقاومت به خوردگی داغ پوشش سرامیکی YSZ و پوششهای نانوکامپوزیتیAl- YSZ۲O۳با درصدهای مختلف آلومینا (Wt ۲۰ ,۱۵ ,۱۰ ,۵) بر روی سوپرآلیاژ اینکونل ۷۳۸ با روش رسوبدهی الکتروفورتیک مورد بررسی قرار گرفته است .پوششهای حاصل در دمای محیط و به مدت ۲۴ ساعت تحت عملیات خشک کردن قرار گرفته و سپس برای افزایش چسبندگی بین پوشش /زیرلایه و کاهش عیوب ریزساختاری در دمای ۱۱۵۰ و به مدت ۴ ساعت تفجوشی شدند .ریزساختار و ترکیب شیمیایی پوششهای حاصل به ترتیب با استفاده از میکروسکوپ الکترونی روبشی (SEM) و تفرق پرتوی ایکس (XRD) مورد مطالعه قرار گرفت .مقاومت به خوردگی داغ پوششهای تفجوشیشده با ریختن مقدار mg ۲۰ از مخلوط نمکهای پنتا اکسید وانادیم و سولفات سدیم با نسبت یکسان در مساحتی به ابعادcm
Text of Note
In this study microstructural, adhesion strength, microhardness and hot corrosion of YSZ, YSZ-5, 10, 15, and 20 wt alumina nanocomposite coatings on inconel-738 superalloy substrate by electrophoretic deposition have been studied. The coatings were dried at ambient temperature within 24 hours subsequently the coated samples were sintered at 1150 for 4 hours in order to increase inter-particle bonding and to increase the coating/substrate adhesion strength. The microstructure, phase composition, hardness and adhesion strength of the deposited coatings were studied using scanning electron microscopy (SEM) observations, x-ray diffraction (XRD) analysis, microhardness measurements, Rockwell hardness testing and pullout testing with cross-head speed of 1 mm/min, respectively. Hot corrosion resistance of the coatings was evaluated by equi-weight mixture of vanadium pentoxide and sodium sulfate applied onto the samples' surface followed by heating the samples in the furnace at 1000 for 4 hours. The corroded coatings were characterized using SEM and XRD techniques to capture phase and morphological changes. The effects of the suspension and the electrophoretic process variables including Al2O3 concentration, suspension conductivity and I2 concentration, deposition voltage, deposition time, and sintering temperature were studied. The results showed that the presence of alumina in the coatings interparticle adhesion and improves the coating/substrate adhesion strength. Increasing Al2O3 content in YSZ-Al2O3 coatings reduces the porosity and results in formation of free-crack coatings which yields to improvement in the microhardness of the deposited coatings. Alumina addition improves sintering in the nanocomposite YSZ-Al2O3 coatings. Increasing alumina in coatings causes enhancement in the hot corrosion resistance of the coatings. The greatest corrosion resistance was observed for the YSZ-20 Al2O3 nanocomposite coating with a highest XRD peak ratio of t-ZrO2 - m-ZrO2 and the lowest amount of YVO4 crystals.
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PARALLEL TITLE PROPER
Parallel Title
Electrophoretic Deposition and Characterization of YSZ-Al۲O۳ Nanocomposite Coatings