JMMCE  Vol.3 No.1 , January 2015
Hot Corrosion Behavior of Superalloy in Different Corrosive Environments
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.

Cite this paper
Kamal, S. , Sharma, K. , Abdul-Rani, A. (2015) Hot Corrosion Behavior of Superalloy in Different Corrosive Environments. Journal of Minerals and Materials Characterization and Engineering, 3, 26-36. doi: 10.4236/jmmce.2015.31004.
References
[1]   Zhang, J.S., Hu, Z.Q., Murata, Y., Morinaga, M. and Yukawa, N. (1993) Design and Development of Hot Corrosion- Resistant Nickel-Base Single-Crystal Superalloys by the d-Electrons Alloy Design Theory: Part I. Characterization of the Phase Stability. Metallurgical Transactions A, 24, 2443-2450.

[2]   Li, J. and Wahi, R.P. (1995) Investigation of Lattice Mismatch in the Polycrystalline Nickel-Base Superalloy IN738LC: Influence of Heat Treatment and Creep Deformation. Acta Metallurgica et Materialia, 43-2, 507-517.

[3]   Wang, Y., Mukherji, D., Chen, W., Kuttner, T., Wahi, R.P. and Wever, H. (1995) The Cyclic Creep Behavior of Nickel- Base Superalloy IN738LC. 86, 365-370.

[4]   Chen, H., Chen, W., Mukherji, D., Wahi, R.P. and Wever, H. Z. (1995) Cyclic Life of Superalloy IN738LC under In- Phase and Out-of-Phase Thermo-Mechanical Fatigue Loading. Z. Metalkd, 86-6, 423-427.

[5]   Maledi, N.B., Potgieter, J.H., Sephton, M., Cornish, L.A., Chown, L. and Suss, R. (2006) International Platinum Conference “Platinum Surges Ahead”. The Southern African Institute of Mining and Metallurgy, Sun City, 81-90.

[6]   Bettge, D., Osterle, W. and Ziebs, J.Z. (1995) Temperature Dependence of Yield Strength and Elongation of the Nickel-Base Superalloy IN738LC and the Corresponding Microstructural Evolution. Z. Metalkd, 86-3, 190-197.

[7]   Esmaeili, S., Engler-Pinto Jr., C.C., Ilschner, B. and Rezai-Aria, F. (1995) Interaction between Oxidation and Thermo- Mechanical Fatigue in IN738LC Superalloy. Scripta Metallurgica et Materiallia, 33, 1777-1781.

[8]   Rocca, E., Steinmetz, P. and Moliere, M. (2003) Revisiting the Inhibition of Vanadium-Induced Hot Corrosion in Gas Turbines. Journal of Engineering for Gas Turbines and Power, 125, 1-9.
http://dx.doi.org/10.1115/1.1456095

[9]   Deb, D., Iyer, S.R. and Radhakrishnan, V.M. (1996) A Comparative Study of Oxidation and Hot Corrosion of a Cast Nickel Base Superalloy in Different Corrosive Environments. Materials Letters, 29, 19-23. http://dx.doi.org/10.1016/S0167-577X(96)00109-7

[10]   Stringer, J. (1977) Hot Corrosion of High-Temperature Alloys. Annual Review of Materials Science, 7, 477-509. http://dx.doi.org/10.1146/annurev.ms.07.080177.002401

[11]   Hejwowski, T. (2006) Investigations of Corrosion Resistance of Fe-, Ni- and Co-Based Hardfacings. Vacuum, 80, 1386-1390. http://dx.doi.org/10.1016/j.vacuum.2006.01.021

[12]   Otero, E., Pardo, A., Hernaez, J. and Perez, F.J. (1992) The Corrosion of Some Superalloys (at 1000 K) in Molten Eu- tectic Mixture 60% V2O5-40% Na2SO4. The Influence of the Oxygen and Carbon Residues. Corrosion Science, 34, 1747-1757.
http://dx.doi.org/10.1016/0010-938X(92)90006-O

[13]   Gurrappa, I. (1999) Hot Corrosion Behavior of CM 247 LC Alloy in Na2SO4 and NaCl Environments. Oxidation of Metals, 51, 353-382.
http://dx.doi.org/10.1023/A:1018831025272

[14]   Choi, H., Yoon, B., Kim, H. and Lee, C. (2002) Isothermal Oxidation of Air Plasma Spray NiCrAlY Bond Coatings. Surface and Coatings Technology, 150, 297-308.
http://dx.doi.org/10.1016/S0257-8972(01)01557-2

[15]   Kamal, S., Jayaganthan, R. and Prakash, S. (2010) Evaluation of High Temperature Cyclic Oxidation and Hot Corrosion Behaviors of Superalloys at 900ºC. Bulletin of Material Science, 33, 299-306.

[16]   Mckee, D.W., Shore, D.A. and Luthra, K.L. (1978) The Effect of SO2 and NaCl on High Temperature Hot Corrosion. Journal of the Electrochemical Society, 3, 411-419.
http://dx.doi.org/10.1149/1.2131463

[17]   Shinata, Y. (1987) Accelerated Oxidation Rate of Chromium Induced by Sodium Chloride. Oxidation of Metals, 27, 315-322. http://dx.doi.org/10.1007/BF00659274

[18]   Sidhu, T.S., Malik, A., Prakash, S. and Agrawa, R.D. (2006) Cyclic Oxidation Behavior of Ni- and Fe-Based Superalloys in Air and Na2SO4-25% NaCl Molten Salt Environment at 800ºC. International Journal of Physical Sciences, 1, 027-033.

[19]   Sachs, K. (1958) Accelerated High Temperature Oxidation due to Vanadium Pentoxide. Metallurgia, 167-173.

 
 
Top