سال انتشار: ۱۳۸۶

محل انتشار: دهمین کنگره ملی خوردگی ایران

تعداد صفحات: ۶

نویسنده(ها):

M Saremi – SchoolofMetallurgy and Materials Engineering, University CollegeofEngineering, University ofTehran, Iran
M Kazemi –
P Zackersafaie –

چکیده:

Hot corrosion of super alloys is an important subject which researchers have different opinions on its mechanism and consequently, there is a need for a comparative investigation for getting a reliable result about it. The present work is a comparative study on the hot corrosion behavior of nickel-base
super alloy In-738LC by using electrochemical and weight loss techniques. In the weight loss method changes in weight vs. time is recorded and there is only a chance to study the microstructure and surface damages in addition to theweight changes. Electrochemical technique has the ability to make a continuous record ofpotential and corrosion current density, and the ability to investigate the surface layer behavior .In this study, the hot corrosion behavior of In-738LC in eutectic melt of Na2S042Owto/ oNaCI in 7500C is studied using the electrochemical technique from both the acidic and basic fluxing pointsofview.
The results indicated that there are three regions in the acidic fluxing zone. Stages I and 2 are initial regions ofhot corrosion, while region 3 is the propagation stage. In region 1 the In-738LC was stable for 700 mV anodic polarization after the corrosion started. In the cathodic or basic fluxing region only one stage was observed. Metallographic studies on the corroded. surfaces indicated penetration of sulfides into the grain. boundaries. It was concluded that In-738LC is resistant at the initial stage of hot corrosion, but its behavior should be improved by coating application.