بررسی اثر دما و غلظت الکترولیت در فرایند الکتروپولیش بر مقاومت به خوردگی آلیاژ اینکونل 718

رحیمی, حامد; صائب نوری, احسان

doi:10.30501/jamt.2018.91404

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

مرکز تحقیقات مواد پیشرفته، دانشکده مهندسی مواد، واحد نجف آباد

https://doi.org/10.30501/jamt.2018.91404

چکیده

بهبود مقاومت به خوردگی توسط فرایند الکتروپولیش یکی از راه‌های مهم در فرایند اصلاح سطح می‌باشد. در این تحقیق اثر دو متغیر غلظت اسید پرکلریک و دمای حمام بر فرایند الکتروپولیش و تاثیر آن بر مقاومت به خوردگی آلیاژ اینکونل 718 بررسی شد. جهت بررسی ریزساختار و کیفیت زبری سطح، قبل و بعد از الکتروپولیش به ترتیب از تصاویر میکروسکوپ الکترونی روبشی و آزمون زبری سنجی سطح استفاده شد. جهت تعیین محدوده ولتاژ و جریان الکتروپولیش از منحنی‌های I-V استفاده شد. نتایج نشان داد دستیابی به سطحی یکنواخت و عاری از حفرات تنها در شرایطی حاصل می‌شود که ترکیب الکترولیت حاوی 20 درصد حجمی اسید پرکلریک و دمای حمام برابر °C 15 باشد. تحت شرایط مذکور سرعت الکتروپولیش در مرزدانه‌ها و درون دانه‌ها به یکدیگر نزدیک شده و منجر به ایجاد سطحی صاف و یکنواخت می گردد. حداقل زبری سطح بعد از الکتروپولیش در شرایط بهینه µm 026/0 به دست آمد. نتایج حاصل از آزمون پلاریزاسیون تافل در محلول H₂SO₄+0.01M KSCN 0.5M نشان داد، الکتروپولیش موجب کاهش چگالی جریان خوردگی و نجیب‌تر شدن پتانسل خوردگی در آلیاژ شده است. نمونه الکتروپولیش شده در شرایط بهینه بیشترین مقاومت به خوردگی را از خود نشان داد. دلیل افزایش مقاومت به خوردگی در اثر الکتروپولیش به تشکیل لایه اکسیدی یکنواخت و ریزساختار عاری از حفرات در سطح نسبت داده شد.

کلیدواژه‌ها

عنوان مقاله [English]

Evaluation of temperature and electrolyte concentration in electropolishing process on corrosion resistance of Inconel 718 alloy

نویسندگان [English]

Hamed Rahimi
Ehsan Saebnoori

Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch

چکیده [English]

Improvement of the corrosion resistance capability by the electropolishing (EP) is one of the most importance process surface modification. In this paper, the effects of two variables perchloric acid concentration and bath temperature on the electropolishing process and the corrosion resistance performance of the Inconel 718 alloy were studied. Evaluation of microstructure and surface roughness quality before and after electropolishing process by the scanning electron microscopy (SEM) and surface roughness test were used, respectively. In order to determine voltage range and current electropolishing to I-V curves were used. The results showed that, obtain to uniform surface and without pores can be achieved only under the conditions has the electrolyte composition as 10 vol% H₂O -70 vol% CH₃COOH -20 vol% HClO₄ and bath temperature is 15 °C. Electropolishing rate in the above conditions at the grain boundaries and inside the grains came close together and lead to a smooth and uniform surfaces. The minimum surface roughness after electropolishing on the above condition amount 0.026 μm obtained. The results of the TOEFL polarization test in a solution of 0.5M H2SO4 + 0.01M KSCN indicated, electropolishing Inconel 718 alloy reduces the corrosion current density and become more Noble in potential (E_corr). Electropolished samples under optimized conditions has exhibited the highest resistance to corrosion. The reason improving in the corrosion resistance Inconel 718 alloy by electropolishing that was attributed to the formation of very uniform oxide layer on surface and microstructure free of cavities.

کلیدواژه‌ها [English]

Electropolishing
Inconel 718 alloy
Perchloric Acid
Corrosion resistance

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مواد و فناوری‌های پیشرفته

بررسی اثر دما و غلظت الکترولیت در فرایند الکتروپولیش بر مقاومت به خوردگی آلیاژ اینکونل 718

مراجع

مراجع

[13] Han, Y., Han, E,H., Peng, Q., Ke, W., “Effects of electropolishing on corrosion and stress corrosion cracking of Alloy 182 in high temperature water”, Corrosion Science, 2017, Vol. 121, Pp. 1-10.

[14] Babilas, D., Urbanczyk, E., Sowa, M., Maciej, A., Korotin, D.M., Zhidkov, I.S., Basiaga d, M., Borkowicz, M.K., Warszynska, L.S., Pamuł, E., “On the electropolishing and anodic oxidation of Ti-15Mo alloy”, Electrochimica Acta, 2016, Vol. 205, Pp. 256-265.

دوره 7، شماره 2
شهریور 1397
صفحه 31-39

بررسی اثر دما و غلظت الکترولیت در فرایند الکتروپولیش بر مقاومت به خوردگی آلیاژ اینکونل 718

مراجع

مراجع

[13] Han, Y., Han, E,H., Peng, Q., Ke, W., “Effects of electropolishing on corrosion and stress corrosion cracking of Alloy 182 in high temperature water”, Corrosion Science, 2017, Vol. 121, Pp. 1-10.

[14] Babilas, D., Urbanczyk, E., Sowa, M., Maciej, A., Korotin, D.M., Zhidkov, I.S., Basiagad, M., Borkowicz, M.K., Warszynska, L.S., Pamuł, E., “On the electropolishing and anodic oxidation of Ti-15Mo alloy”, Electrochimica Acta, 2016, Vol. 205, Pp. 256-265.

دوره 7، شماره 2شهریور 1397صفحه 31-39

[14] Babilas, D., Urbanczyk, E., Sowa, M., Maciej, A., Korotin, D.M., Zhidkov, I.S., Basiaga d, M., Borkowicz, M.K., Warszynska, L.S., Pamuł, E., “On the electropolishing and anodic oxidation of Ti-15Mo alloy”, Electrochimica Acta, 2016, Vol. 205, Pp. 256-265.

دوره 7، شماره 2
شهریور 1397
صفحه 31-39