TITLE:
Hot Corrosion Behavior of Superalloy in Different Corrosive Environments
AUTHORS:
Subhash Kamal, Korada Viswanath Sharma, A. M. Abdul-Rani
KEYWORDS:
Hot Corrosion, Superalloy, Superfer 800H, Cyclic Conditions, Spinel NiCr2O4
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.3 No.1,
January
9,
2015
ABSTRACT: Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high temperature applications. The present work investigates hot corrosion behaviour of superfer 800H exposed to two different molten salt environments Na2SO4 + 60% V2O5 and Na2SO4 + 5% V2O5 + 5% NaCl respectively, at 900oC under cyclic conditions. The weight change measurements made on during the experiments are used to determine the kinetics of hot corrosion. It is observed that the formation of scale rich in Cr2O3, NiO and spinel NiCr2O4 has contributed for the better hot corrosion resistance of superfer 800H. Inspection for 10, 20, 35 and 50 cycles reveals that after 10 cycles Crack has been initiated in the scale and it is clearly visible in the presence of NaCl salt. On subsequent cycles, crack propagates perpendicular to surface and as it encounters inclusions.