بررسی رفتار خوردگی حفره‌ای کامپوزیت Al-nano ZrO2 تولید شده به روش اتصال نورد تجمعی
محورهای موضوعی : خوردگی و حفاظت مواد
1 - دانشگاه شیراز
2 - دانشگاه شیراز
کلید واژه: نانوکامپوزیت, اتصال‌نوردتجمعی, پلاریزاسیون سیکلی,
چکیده مقاله :
در این تحقیق به بررسی رفتار خوردگی حفره‌ای نانو کامپوزیت Al-nano ZrO2 تولید شده به روش اتصال نورد تجمعی (ARB) پرداخته شده است. ورق های آلیاژ آلومینیوم با ابعاد mm 1×40×250 آنیل شده در دمای k 623 و فشار اتمسفر محیط،و پودر ZrO2 با اندازۀ میانگینnm 40 به عنوان مادۀ اولیه استفاده گردیدند.کامپوزیت Al- nano ZrO2 طی 5 سیکل ساخته شده است. به منظور انجام آزمون های الکتروشیمیایی، نمونه های مستطیلی با ابعاد mm1×10×10 بریده شده، به سیم مسی متصل و سپس مانت سرد گردیدند.پتانسیل مدار باز (OCP) نمونه ها پس از 24 ساعت غوطه وری در آب دریای مصنوعی (3.5 %wt NaCl) اندازه گیری شد و سپس تست های پلاریزاسیون سیکلی در رنج پتانسیل 25/0- تا 1 ولت نسبت به OCP و با سرعت روبش mv/s 1 انجام گردید.نتایج آزمون پلاریزاسیون سیکلی حاکی از کاهش مقدار Eb نمونه نانو کامپوزیتی با افزایش تعداد سیکل های نورد می باشد. همچنین با افزایش تعداد پاس نورد مقادیر Eb-Erp کاهش می‌یابد که نشان می دهد لایه پسیو مجدد، راحت تر تشکیل گردیده است.تصاویر SEM نشان دهنده کاهش اندازه و توزیع یکنواخت حفره‌های ایجاد شده بر روی نمونه ها، با افزایش تعداد پاس های نورد می باشد.
In this study, the pitting corrosion behaviour of Al-Nano ZrO2 Nano composites fabricated by Accumulative Roll bonding (ARB) process was investigated. Strips of 1050-aluminum alloy of length 250 mm, width of 40 mm, and thickness of 1 mm annealed at 623K in ambient atmosphere and analytical grade of ZrO2 powder with an average size of 40nm were used as raw materials. The Al-Nano ZrO2 composite was produced in 5 cycles. For electrochemical measurements, the square specimens of 10mm×10mm×1mm were cut, connected to copper wires and cold mounted. The open circuit potentials (OCP) of the specimens were measured after 24h immersion in the artificial seawater (3.5wt% NaCl), then Cyclic Polarization test were carried out at range of -0.25 / 1 v with respect to OCP and scan rate of 1mV/s. The results of Cyclic Polarization test indicated that when rolling cycles increase, the Eb and Eb-Erp decrease. The repassivation improved by decrease in Eb-Erp. SEM images represent the decrease and uniform distribution of pits on the surface of samples by increasing the rolling cycles.
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