تاثیر الکترولیت بر ریزساختار و خواص خوردگی پوشش اکسیداسیون الکترولیتی پلاسمایی روی آلیاژ آلومینیم 7075

نوع مقاله : علمی و پژوهشی

نویسندگان

• عرفان پیرهادی نوری ¹
• سعید رضا الله کرم ²
• مهرناز قراگوزلو ³

¹ دانشکده مهندسی متالورژی و مواد، دانشکدگان فنی دانشگاه تهران

² دانشکده مهندسی متالورژی و مواد ، دانشکدگان فنی، دانشگاه تهران.

³ گروه نانو فناوری پژوهشگاه رنگ

10.22067/jmme.2025.89503.1153

چکیده

اکسیداسیون الکترولیتی پلاسمایی (PEO) روشی موثر برای بهبود مقاومت به خوردگی آلیاژ آلومینیم 7075 است. الکترولیت یکی از مهمترین عوامل تاثیرگذار روی خواص پوشش حاصل می‌باشد. در این تحقیق جهت بررسی تاثیر الکترولیت، پوشش‌دهی توسط اکسیداسیون الکترولیتی پلاسمایی (PEO) در الکترولیت‌های سیلیکاتی، فسفاتی و سیلیکاتی-فسفاتی بر روی آلیاژ AA7075 انجام شد. ضخامت پوشش‌ها توسط ضخامت‌سنج ادی‌کارنت اندازه‌گیری شد. مشخص شد که افزایش غلظت سیلیکات موجب افزایش سرعت رشد پوشش می‌شود. با افزایش غلظت سیلیکات از 5 به 10 گرم بر لیتر، ضخامت پوشش از 7 به 5/14 میکرومتر رسید. ریزساختار و عناصر تشکیل‌دهنده پوشش‌های حاصل توسط SEM مجهز به آشکارساز EDS بررسی شد. مشخص شد حضور فسفات سدیم در الکترولیت، ضمن کند کردن سرعت رشد پوشش، منجر به کاهش 6/10 درصدی تخلخل آن نیز می‌شود. مقاومت به خوردگی پوشش‌ها در محلول 5/3 درصد NaCl توسط آزمون EIS ارزیابی شد. مشاهده شد |Z| برای پوشش سیلیکاتی-فسفاتی نسبت به پوشش سیلیکاتی 89 درصد بیشتر است. بنابراین الکترولیت سیلیکاتی-فسفاتی با توجه به تخلخل کمتر بهترین خواص خوردگی را نشان داد.

کلیدواژه‌ها

• آلومینیم 7075
• پوشش اکسیداسیون الکترولیتی پلاسمایی
• خوردگی

موضوعات

• خوردگی و اکسیداسیون

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عنوان مقاله [English]

The effect of electrolyte on the microstructure and corrosion properties of plasma electrolytic oxidation coating on AA7075

نویسندگان [English]

• Erfan Pirhadi nori ¹
• Saeed Reza Allahkaram ²
• mehrnaz gharagozlou ³

¹ School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran

² School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran

³ Department of Nanomaterials and Nanocoatings

چکیده [English]

Abstract: Plasma electrolytic oxidation (PEO) is an effective method to improve the corrosion resistance of 7075 aluminum alloy. Electrolyte plays a crucial role in determining the properties of the final coating. In this research, the effect of electrolyte on plasma electrolytic oxidation (PEO) coatings formed on AA7075 alloy in silicate, phosphate, and silicate-phosphate electrolytes was investigated. The thickness of the coatings was measured by an Eddy-current thickness gauge. It was found that increasing the concentration of silicate increases the growth rate of the coating. Increasing the silicate concentration from 5 to 10 g/L led to a coating thickness increase from 7 to 14.5 µm. The microstructure and constituent elements of the coatings were examined by SEM equipped with an EDS detector. The presence of sodium phosphate in the electrolyte slows the coating's growth rate and reduces its porosity by 10.6 percent. The corrosion resistance of coatings was evaluated in 3.5% NaCl solution by EIS test. It was found that |Z| is 89% higher for the silicate-phosphate coating than the silicate coating. Silicate-phosphate electrolyte showed the best corrosion resistance behavior due to its lower porosity.

کلیدواژه‌ها [English]

• AA7075
• Plasma Electrolytic Oxidation
• Corrosion

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