High Temperature Oxidation Behaviour of Nimonic - 115 Alloy in Presence of Sodium Salts at 850OC

Document Type: Research Article

Author

Department of Chemistry, Faculty of Science and Technology,University College of Science and Technology Malaysia (KUSTEM),Mengabang Telipot, 21030 Kuala Terengganu, Terengganu Darul Iman, MALAYSIA

Abstract

The high temperature oxidation behaviour of Nimonic-115 industrial alloy has been investigated in presence of  NaNO3, Na2CO3 and Na2O2 at 850oC in flowing air. The oxidation kinetics and effect of salt deposition for the period of 48 h were studied. The scale morphologies were determined on the basis of X-ray diffraction analysis and Scanning electron microscopic techniques. It has been shown that the alloy corrodes at different rate in presence of different sodium salts although each salt contains the same amount of sodium equivalent to Na2O.

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[1] Luthra,  K.L.  and  Shores, D. A.,   Mechanism  of Na2SO4-induced corrosion at 600-900°C, J. Electrochem. Soc., 127, 2202  (1980).

[2] Iyer, V.R. and Devereux, O. F., J. Electrochem. Soc., 132,  1098 (1985).

[3] Kawakami, M., Goto, K.S. and Rapp, R.A., Transac. Iron and Steel Inst. Japan, 20, 646 (1980).

[4] Hancock, P., “The role of halides in high temperature gas corrosion”, Proc. On High Temperature Metal Halides Chemistry, Eds. D.L. Hiderbrand and D. Cubeeciotti, The Electrochem. Soc., Princeton, 645 (1978).

[5] Rapp, R.A., “Materials selection and problems for molten carbonate cells”, Molten Carbonate Fuel Cell Workshop, Oak Ridge National Laboratory, Oct.31-Nov.2, (1978).

[6] Picard, G., Lefebure, L. M. and Tremillon, B. L., “Thermodynamic study of iron corrosion in NaNO3-NaNO2 mixtures”, Proc. Sth Tntnl. Conf. on Molten salts, Las Vegas, Oct. pp. 13-18 ( 1985 ).

[7] Misbahul, M. A., Hot Corrosion Behaviour of Inconel-600 Alloy in Presence NaCl and Na2CO3 at 850 o C, Prakt. Metallogr., 30, 239 (1993 ).

[8] Misbahul, M. A., and Ahmad, M.B., Effect of Sodium Nitrate and Sodium Peroxide Deposits on High Temeperature Oxidation of Nimonic-105 Alloy at 700 o C, Corros. Sci. & Protech. Tech., 7, 321 ( 1995 ).

[9] Malik, A. U., Misbahul, M. A. and Ahmed, S., Hot Corrosion Behaviour of 18Cr:8Ni Austenitic Stell in Presence of Na2SO4 and Transition Metal Salts, Transact. Jpn. Inst. Met., 25, 169 ( 1984 ).

[10] Deverux, O.F., Kim, O. F. and Yeum, K. S.,  Reaction at the Corroding Nickel Electrode in Molten Carbonate under CO/CO2 Atmosphere, Corros. Sci., 23,  205 (1983).

[11] Misbahul, M. A., The CsCl-and CsNO3-induced High Temperature Oxidation of Nimonic-90 Alloy at 1123 K, Appl. Surf. Sci., 115, 355 (1997).