Comparative Study of Microstructure, Phase Composition, and Oxidation Resistance of CoNiCrAlY Coating Deposited by HVOF and LPPS processes

Subject Areas :

pejman zamani moghaddam ¹ , Zia Valefi ²

1 - surface and coating engineering, faculty of materials, Malek Ashtar university of technology, Tehran, Iran
2 - surface and coating engineering, faculty of materials engineering, Malek Ashtar University of Technology, Tehran, Iran

Received: 2023-02-06 Accepted : 2024-07-02 Published : 2024-03-04

Keywords: CoNiCrAlY Coating, HVOF, LPPS, Thermal spray, High-temperature oxidation.,

Abstract :

In this research, CoNiCrAlY powder was deposited by high-velocity oxy-fuel (HVOF) and low-pressure plasma spraying (LPPS) processes on IN738 nickel-based superalloy substrates. The high-temperature oxidation test was performed on the coatings at a temperature of 1050 ̊C and a time of 200 hours in a muffle furnace. The microstructure and phase composition of the coatings were investigated by SEM and XRD before and after the oxidation test. The porosity (volume percentage) and surface roughness (micrometer) were measured for HVOF coating as 0.6 and 4.4, and for LPPS coating as 2 and 6.62, respectively. The HVOF coating consisted of γ-CoNiCr and β-(Co,Ni)Al, while the LPPS coating included a single phase γ-CoNiCr. The disappearance of the β phase in the LPPS coating after spraying was due to dissolution in the plasma jet and its non-recovery in the conditions of rapid quenching and non-equilibrium solidification. This phase was recovered after heat treatment. The microstructure of the LPPS coating had much less oxide than the HVOF coating due to depositing at low oxygen pressure in the vacuum chamber. After 200 hours of oxidation test, the amount of β phase (as an oxidation resistance criterion) was completely consumed in the LPPS coating, while the HVOF coating contained the retained β deposits. The average thickness of TGO layer for HVOF and LPPS coatings was 5.2 and 7.1 μm, respectively. The dispersed oxides in the microstructure, lower roughness and denser structure of HVOF coating were reasons for the higher oxidation resistance of HVOF coating than LPPS.

References:

[1] N. Czech & W. Stamm, "Optimisation of MCrAlY Type Coatings for Single Crystal and Convential Cast Gas Turbine Blades", High Temperature Surface Engineering, CRC Press, pp. 61-65, 2020.

[2] A. Niaz, Al-Fuhaid & M. I. Faraz, "Understanding Corrosion Degradation Processes of a Multi-Component CoNiCrAlY-Coating System", Coatings, vol. 12, no. 10, p. 1396, 2022.

[3] E. Bakan, D. E. Mack, G. Mauer, R. Vaßen, J. Lamon & N. P. Padture, "High-temperature materials for power generation in gas turbines", In Advanced ceramics for energy conversion and storage, pp. 3-62, 2021.

[4] پ. ز. مقدم، ر. قاسمی، ب. سعیدی، ح. دهاقین، ف. شهریاری و م. معماری، "تأثیر عملیات حرارتی بر ریزساختار و خواص مکانیکی پوشش Cr3C2-NiCr ایجاد شده توسط فرایند HVOF"، فرآیندهای نوین در مهندسی مواد، دوره 14، شماره 4، صفحه 63-53، 1399.

[5] K. Yuan, R. L. Peng, X. H. Li, S. Johansson & Y. D. Wang, "Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation", Surface and Coatings Technology, vol. 261, pp. 86-101, 2015.

[6] م. طهری، "بهینه‌سازی پارامترهای پاشش حرارتی HVOF، برای بهبود مقاومت به اکسیداسیون پوشش MCrAlY توسط روش سطح پاسخ"، فرآیندهای نوین در مهندسی مواد، دوره 11، شماره 3، صفحه 83-75، 1396.

[7] B. Sudhangshu, "High temperature coating". Elsevier Science & Technology Books, 2007.

[8] J. R. Davis, "Handbook of Thermal Spray Coating". ASM International, 2004.

[9] E. Muehlberger & P. Meyer, "LPPS-thin film processes: overview of origin and future possibilities", Thermal Spray, 2009.

[10] F. Tang, L. Ajdelsztajn & J. M. Schoenung, "Characterization of oxide scales formed on HVOF NiCrAlY coatings with various oxygen contents introduced during thermal spraying", Scripta Materialia, vol. 51, no. 1, pp. 25-29, 2004.

[11] A. Fossati, M. Di-Ferdinando, A. Lavacchi, U. Bardi, C. Giolli & A. Scrivani, "Improvement of the isothermal oxidation resistance of CoNiCrAlY coating sprayed by High Velocity Oxygen-Fuel", Surface and Coatings Technology, vol. 204, no. 21-22, pp. 3723-3728, 2010.

[12] M. D. Ferdinando, A. Fossati & A. L. U. Bardi, "Isothermal oxidation resistance comparison between air plasma sprayed, vacuum plasma sprayed and high velocity oxygen fuel sprayed CoNiCrAlY bond coats". Surface and Coatings Technology, vol. 204, no. 15, pp. 2499-2503, 2010.

[13] W. Nowak, D. Naumenko, G. Mor, F. Mor, D. E. Mack, "Effect of processing parameters on MCrAlY bondcoat roughness and lifetime of APS–TBC systems", Surface and coatings technology, vol. 260, pp.82-89, 2014.

[14] P. L. Fauchais, M. I. Boulos & J. V. R. Heberlein, "Thermal Spray Fundamentals from Powder to Part". Springer, Boston, MA, 2014.

[15] M. Abbas, M. Smith & R. Munroe, "Microstructural investigation of bonding and melting-induced rebound of HVOF sprayed Ni particles on an aluminum substrate", Surface and Coatings Technology, vol. 402, p. 126353, 2020.

[16] K. Yuan & Z. R. Zheng, "Study on the Oxidation Behavior of LPPS MCrAlY Coatings at High Temperature: Part II Coating Microstructure Development", Materials Science Forum, vol. 1035, pp. 584-590, 2021.

[17] M. Tahari, "The effect of heat treatment and thermal spray processes on the grain growth of nanostructured composite CoNiCrAlY/YSZ powders", Journal of Alloys and Compounds, vol. 646, pp. 372-379, 2015.

[18] C. T. Sims, N. S. Stoloff & W. C. Hagel, "Superalloys II: high temperature materials for aerospace and industrial power", John Wiley & Sons, New York, 1987.

[19] M. Durand-Charre, "The microstructure of superalloys", J. H. Davidson, Gordon and breach science publishers, 1997.

[20] H. Chen & A. Rushworth, "Effects of oxide stringers on the β-phase depletion behaviour in thermally sprayed CoNiCrAlY coatings during isothermal oxidation", Journal of Materials Science & Technology, vol. 45, pp. 108-116, 2020.

[21] P. Zamani & Z. Valefi, "A comparative investigation of microstructure and high-temperature oxidation resistance of HVOF-sprayed CoNiCrAlY/nano-Al2O3 composite coatings using satellited powders", International Journal of Minerals, Metallurgy and Materials, in press, 2023.

[22] N. Rana, R. Jayaganthan & S. Prakash, "Stepwise oxidation mechanism of HVOF sprayed NiCrAlY coatings in air", Transactions of the Indian Institute of Metals, vol. 67, pp. 393-400, 2014.

[23] A. Feuerstein, J. Knapp, T. Taylor, A. Ashary, A. Bolcavage & N. Hitchman, "Technical and economic aspects of current thermal barrier coating systems for gas turbine engines by thermal spray and EBPVD: A review", Journal of Thermal Spray Technology, vol. 17, no. 2, pp. 199-213, 2008.

[24] F. T. Talboom, R. C. Elam & L. W. Wilson, "Evaluation of advanced superalloy protection systems". ReprotCR7813, Houston, NASA, pp. 235-240, 1970.

[25] M. Shibata, S. Kuroda, H. Murakami, M. Ode, M. Watanabe & Y. Sakamoto, "Comparison of microstructure and oxidation behavior of CoNiCrAlY bond coatings prepared by different thermal spray processes", Materials transactions, vol. 47, no. 7, pp.1638-1642, 2006.


[26] L. Y. Ni, Z. L. Wu & C. G. Zhou, "Effects of surface modification on isothermal oxidation behavior of HVOFsprayed NiCrAlYcoatings", Progress in Natural Science: Materials International, vol. 21, no. 2, pp. 173-179, 2011.

[27] F. Tang, L. Ajdelsztajn, G. E. Kim, V. Provenzano & J. M. Schoenung, "Effects of surface oxidation during HVOF processing on the primary stage oxidation of a CoNiCrAlY coating", Surface and Coatings Technology, vol. 185, no. 2-3, pp. 228-233, 2004.

[28] W. X. Weng, Y. M. Wang, Y. M. Liao, C. C. Li & Q. Li, "Comparison of microstructural evolution and oxidation behaviour of NiCoCrAlY and CoNiCrAlY as bond coats used for thermal barrier coatings", Surface and Coatings Technology, vol. 352, pp. 285-294, 2018.