The effect of Pt on type II hot corrosion behavior of Si-aluminide coatings with lower silicon than the critical amount
Subject Areas :
Seyed Amir
Azarmehr
1
(Iranian Research Organization for Science and Technology (IROST))
kourosh
shirvani Jozdani
2
(Iranian Research Organization for Science and Technology (IROST))
Keywords: Platinum, Silicon-aluminide coating, Type II hot corrosion, acidic fluxing, Superalloy GTD-111,
Abstract :
In this paper, the effect of adding a low amount of platinum to slurry Si-modified aluminide coatings containing silicon less than the amount required to provide complete protection in these coatings is investigated. In addition to the coatings characterization, the role of platinum on the type II hot corrosion behavior of coatings has been discussed. To create silicon and silicon-platinum aluminide coatings, a slurry silicoaluminzing method was applied to samples of Ni-base superalloy GTD-111 specimens, which was previously Pt-electroplated on some of them with a thickness of 2 μm. The amount of silicon in the slurry was 10% by weight relative to total solid of the slurry, so that the amount of silicon in the coating is less than the critical amount required for complete protection. The type II hot corrosion test was carried out using a furnace method with Na2SO4-60mol% V2O5 at 700 °C. After 20 hours of hot corrosion, Al2O3 protective oxide and non-protective oxide NiAl2O4 were detected in silicon-platinum- and silicon-aluminide coatings, respectively. In the absence of platinum, the Ni3V2O8 phase was also found to be a product of NiO and NiAl2O4 dissolution in type-II hot corrosion condition. At the end of the 80-hour hot corrosion, unlike the silicon-aluminide coating, silicon remained in the silicon-platinum-aluminide coating structure.
[1] C. Sims, “The superalloysˮ, Edited by CT Sims and WC Hagel, John Wiley Pub., New York, 1972.
[2] J. Göbel & F. Pettit, “Na2SO4-induced accelerated oxidation (hot corrosion) of nickel”, Met. and Mat. Trans. B, Vol. 1, pp. 1943-1954, 1970.
[3] K. Luthra & D. Shores, “Mechanism of Na2SO4Induced Corrosion at 600°–900°C”, J. of the Elec. Soc., Vol. 127, pp. 2202-2210, 1980.
[4] J. Göbel, F. Pettit & G. Goward, “Mechanisms for the hot corrosion of nickel-base alloys”, Met. and Mat. Trans. B, Vol. 4, pp. 261-278, 1973.
[5] R. A. Rapp & K. Goto, “The hot corrosion of metals by molten salts, Proceedings of the Second International Symposium on Molten Salts”, Physical Electrochemistry Division, Electrochemical Society, pp. 159, 1981.
[6] R. A. Rapp, “Chemistry and electrochemistry of hot corrosion of metals”, Mat. Sci. and Eng., Vol. 87, pp. 319-327, 1987.
[7] R. A. Rapp & Y. S. Zhang, “Hot corrosion of materials: fundamental studies”, JOM, Met. and Mat. Soc., Vol. 46, pp. 47-55, 1994.
[8] R. A. Rapp, “Hot corrosion of materials: a fluxing mechanism?”, Corr. Sci., Vol. 44, pp. 209-221, 2002.
[9] M. Moliere & J. Sire, “Heavy duty gas turbines experience with ash-forming fuels”, J. de Phys. IV Coll., pp. 719-730, 1993.
[10] N. Birks, G. H. Meier & F. S. Pettit, “Introduction to the high temperature oxidation of metals”, Cambridge University Press, 2006.
[11] Y. Zhang & R. Rapp, “Solubilities of CeO2, HfO2 and Y2O3 in fused Na2SO4-30 mol% NaVO3 and CeO2 in pureNa2SO4 at 900°C”, Corrosion, Vol. 43, pp. 348-352, 1987.
[12] Y. Hwang & R. Rapp, “Thermochemistry and solubilities of oxides in sodium sulfate-vanadate solutions”, Corrosion, Vol. 45, pp. 933-937, 1989.
[13] R. Streiff & D. Boone, “Corrosion resistant modified aluminide coatings”, J. of Mat. Eng., Vol. 10, pp. 15-26, 1988.
[14] G. Meier & F. Pettit, “High-temperature corrosion of alumina-forming coatings for superalloys”, Sur. and Coat. Tech., Vol. 39, pp. 1-17, 1989.
[15] G. Tatlock & T. Hurd, “Platinum and the hot corrosion behaviour of a nickel based superalloy”, Materials and Corrosion, Vol. 41, pp. 710-715,1990.
[16] M. N. Task, B. Gleeson, F. S. Pettit & G. H. Meier, “Compositional factors affecting protective alumina formation under type II hot corrosion conditions”, Oxid. of Met., Vol. 80, pp. 541-552, 2013.
[17] K. Shirvani & A. Rashidghamat, “Evolution of oxide scale on aluminide and Pt-aluminide coatings exposed to type I (870°C) hot corrosion”, Oxid. of Met., Vol. 85, pp. 75-85, 2016.
[18] H. Grünling & R. Bauer, “The role of silicon in corrosion-resistant high temperature coatings”, Thin Solid Films, Vol. 95, pp. 3-20, 1982.
[19] T. W. Kerr, “Hot corrosion and oxidation studies of pure nickel and Ni-Cr, Ni-Si and Ni-Cr-Si alloys at 1000°C”, DTIC-ADA024708, 1975.
[20] B. G. Kim, G. M. Kim & C. J. Kim, “Oxidation behavior of TiAl-X (X= Cr, V, Si, Mo or Nb) intermetallics at elevated temperature”, Scr. Met. et Mat., Vol. 33, pp. 1117-1125, 1995.
[21] B. Li, B. Gleeson, “Effects of silicon on the oxidation behavior of Ni-base chromia-forming alloys”, Oxid. of Met., Vol. 65, pp. 101-122, 2006.
[22] K. Shirvani, M. Saremi, A. Nishikata & T. Tsuru, “The role of silicon on microstructure and high temperature performance of aluminide coating on superalloy In-738LC”, Mat. Trans., Vol. 43, pp. 2622-2628, 2002.
[23] D. Z. Shi & R. A. Rapp, “Solubility of SiO2 in fused Na2SO4 at 900°C”, J. Electrochem. Soc., Vol. 133, pp. 849-850, 1986.
[24] G. E. Creech & M. J. Barber, “Method of forming platinum-silicon-enriched diffused aluminide coating on a superalloy substrate, General Motors Coorporation”, US 5, Vol. 057, pp. 196, 1991.
[25] B. R. Rose & P. R. Lavery, “Platinum group silicide modified aluminide coating process and products”, Walbar Inc., US 5, Vol. 492, pp. 726, 1996.
[26] B. G. McMordie & T. A. Kircher, “Platinum enriched, silicon-modified corrosion resistant aluminide coating”, Sermatech International, Inc., US 5, Vol. 650, pp. 235, 1997.
[27] S. A. Azarmehr, K. Shirvani, M. Schütze & M. Galetz, “Microstructural evolution of silicon-platinum modified aluminide coatings on superalloy GTD-111”, Sur. and Coat. Tech., Vol. 321, pp. 455-463, 2017.
[28] K. Shirvani, M. Saremi & Y. Yamamoto, “The approaches to thin film preparation and TEM observations on slurry Si-modified aluminide coatings”, Mat. and Corr., Vol. 57, pp. 182-184, 2006.
[29] M. Galetz, X. Montero & H. Murakami, “Novel processing in inert atmosphere and in air to manufacture high‐activity slurry aluminide coatings modified by Pt and Pt/Ir”, Mat. and Corr., Vol. 63, pp. 921-928, 2012.
[30] H. M. Tawancy, N. Sridhar, N. M. Abbas & D. Rickerby, “Comparative thermal stability characteristics and isothermal oxidation behavior of an aluminized and a Pt-aluminized Ni-base superalloy”, Scr. Met. et mat., Vol. 33, pp. 1431-1438, 1995.
[31] B. M. Warnes, F. S. Pettit & G. H. Meier, “Hot-corrosion resistance of Ni–Cr–Al–Y and Ni–18% Si alloys in sulfate eutectic and sulfate plus vanadate melts at 973 K”, Oxid. of Met., Vol. 58, pp. 487-498, 2002.
[32] M. Seiersten & P. Kofstad, “Sodium vanadate-induced corrosion of nickel and MCrAIY coatings on Inconel 600”, Mat. Sci. and Tech., Vol. 3, pp. 576-583, 1987.
[33] M. Seiersten, H. J. Rätzer‐Scheibe & P. Kofstad, “Sodium vanadate induced corrosion of MCrAlY coatings–Burner rig studies”, Mat. and Corr., Vol. 38, pp. 532-540, 1987.
[34] E. M. Levin, C. R. Robbins, H. F. McMurdie & M. Reser, American Cer. Soc., Phase diagrams for ceramists, 1964.
[35] B. Gleeson, W. Wang, S. Hayashi & D. J. Sordelet, “Effects of platinum on the interdiffusion and oxidation behavior of Ni-Al-based alloys”, Mat. Sci. Forum, pp. 213-222, 2004.
[36] K. A. Marino & E. A. Carter, “The effect of platinum on diffusion kinetics in β‐NiAl: implications for thermal barrier coating lifetimes”, Chem. Phys. Chem., Vol. 10, pp. 226-235, 2009.
[37] K. A. Marino & E. A. Carter, “The effect of platinum on Al diffusion kinetics in β-NiAl: Implications for thermal barrier coating lifetime”, Acta Mat., Vol. 58, pp. 2726-2737, 2010.
[38] X. Montero & M. C. Galetz, “Coatings for boiler components exposed to vanadium-containing oil ash in oxidizing atmosphere”, Oxid. of Met., Vol. 87, pp. 717-727, 2017.
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