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Effect of Pack Aluminising Conditions on βNiAl Coatings

Authors: A. D. Chandio, P. Xiao


In this study, nickel aluminide coatings were deposited onto CMSX-4 single crystal superalloy and pure Ni substrates by using in-situ chemical vapour deposition (CVD) technique. The microstructural evolutions and coating thickness (CT) were studied upon the variation of processing conditions i.e. time and temperature. The results demonstrated (under identical conditions) that coating formed on pure Ni contains no substrate entrapments and have lower CT in comparison to one deposited on the CMSX-4 counterpart. In addition, the interdiffusion zone (IDZ) of Ni substrate is a γ’-Ni3Al in comparison to the CMSX-4 alloy that is βNiAl phase. The higher CT on CMSX-4 superalloy is attributed to presence of γ-Ni/γ’-Ni3Al structure which contains ~ 15 at.% Al before deposition (that is already present in superalloy). Two main deposition parameters (time and temperature) of the coatings were also studied in addition to standard comparison of substrate effects. The coating formation time was found to exhibit profound effect on CT, whilst temperature was found to change coating activities. In addition, the CT showed linear trend from 800 to 1000 °C, thereafter reduction was observed. This was attributed to the change in coating activities.

Keywords: Microstructure, βNiAl, in-situ CVD, CMSX-4

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R. C. Reed, The superalloys: Fundamentals and Applications, Cambridge University Press, 2006.
[2] V. K. Tolpygo and D. R. Clarke, "Surface rumpling of a (Ni, Pt)Al bond coat induced by cyclic oxidation," Acta Materialia, vol. 48, pp. 3283-3293, 2000.
[3] B. Gleeson, Li B, Sordelet D.J, and Brindley W.J,, "Methods for making high-temperature coatings having Pt metal modified gamma-Ni + gamma'-Ni3Al alloy compositions and a reactive element," U.S. Patent No. 0127695 Patent, 2006.
[4] J. Haynes, Pint BA, Zhang Y, and Wright IG, "Comparison of the cyclic oxidation behavior of b-NiAl, b-NiPtAl and y-y' NiPtAl coatings on various superalloys," Surface Coating Technology, pp. 202, 730, 2007.
[5] A. Chandio, Zhao X., Chen Y., Bai M., and Xiao P.,, " A Study of a βNiAl Bondcoat Deposited onto CMSX-4 Superalloy for Thermal Barrier Applications (Manuscript accepted)." presented at the 39th Int'l Conf & Expo on Advanced Ceramics & Composites (ICACC 2015), Daytona Beach USA, 2015.
[6] X. Zhao, Cernik B., Tang, CC., Thompson SP., and Xiao P, "Stress evolution in a Pt-diffused γ/γ′ bond coat after oxidation," Surface and Coatings Technology, vol. 247, pp. 48-54, 2014.
[7] N. P. Padture, "Thermal Barrier Coatings for Gas-Turbine Engine Applications," Science/AAAS, pp. 296, 280 (2002);.
[8] G. Goward, Protective coatings for high temperature alloys: state of technology, in Source Book on Materials for Elevated-Temperature Applications, Ed. Elihu F. Bradley, : ASM, Metals Park, OH, 1979.
[9] G. Goward, and Bone DH, "Mechanisms of Formation of Diffusion Aluminide Coatings on Nickel-Base Superalloys," Oxidation of Metals vol. 3, pp. 475-495, 1971.
[10] Z. D. Xiang, Burnel-Gray J.S, and Datta P.K,, "aluminide coating formation on nickel-base Superalloys by pack cementation process," Journal of Materials Science pp. 5673-5682, 2001.
[11] G. Moskal, "Thermal barrier coatings: characteristics of microstructure and properties, generation and directions of development of bond," Journal of Achievements in Materials and Manufacturing Engineering, vol. 37, pp. 323-331, 2009.
[12] S. Bose, High temperature coatings: Butterworth-Heinemann, 2011.
[13] B. Sudhangshu, High Temperature Coatings, illustrated ed.: Elsevier 2007.