MCrAlY İçerikli Bağ Kaplamaya Sahip Termal Bariyer Kaplamaların (TBCs) Mikroyapısal Özelliklerinin ve İzotermal Oksidasyon Davranışının İncelenmesi

Öz

Termal bariyer kaplamalar (TBCs), havacılık ve endüstriyel gaz türbin motorlarının sabit ve hareketli parçalarını çevresel olumsuz etkilerden korumak amacıyla kullanılan yüksek sıcaklıkta çalışan koruyucu kaplamalardır. TBC sisteminde, servis süresince oluşabilecek oksidasyon ve korozyon gibi ana hasar oluşum mekanizmalarına karşı koruma sağlaması amacıyla kullanılan altlık malzeme, metalik bağ ve seramik üst kaplama malzemeleri kullanım koşulları altında TBC sisteminin ömrünü belirleyen ana unsurlardır. Bu çalışmada, NiCrAlY içerikli metalik bağ kaplama ve yitriya ile stabilize edilmiş zirkonya (YSZ) içeriğine sahip kaplamalar atmosferik plazma sprey (APS) kaplama yöntemi kullanılarak üretilmiştir. Üretilen TBC sistemi 1150 °C sıcaklık ve 5, 25 ve 50 saatlik zaman süreçlerinde izotermal oksidasyon testlerine maruz bırakılmıştır. Mikroyapısal değişimlerin belirlenebilmesi amacıyla yüksek sıcaklık fırın testleri öncesi ve sonrasında taramalı elektron mikroskopu (SEM) analizi gerçekleştirilmiştir. Metalik bağ ve seramik üst kaplama arayüzey yapısında oluşan oksit yapılarının karakteristik özellikleri yüksek sıcaklık sürecinde zamana bağlı değişimleri ayrıntılı olarak incelenmiş ve değerlendirilmiştir. Oksidasyon sürecine bağlı olarak metalik bağ ve seramik üst kaplama arayüzeyinde ısıl olarak büyüyen oksit tabakası (TGO) yapısının oluşum gösterdiği ve artan oksidasyon sürecine bağlı olan bu tabakanın parabolik olarak büyüme gösterdiği görülmüştür. TGO tabakasının içeriğinin ve büyüme davranışının yüzeyden arayüzeye difüze olan oksijen dışında bağ kaplamada yer alan alaşım elementlerine bağlı değişim gösterdiği tespit edilmiştir.

Anahtar Kelimeler

• Izotermal oksidasyon
• atmosferik plazma sprey (APS)
• NiCrAlY
• yitriya ile stabilize edilmiş zirkonya (YSZ)
• termal bariyer kaplama (TBC)

Investigation of Microstructural Properties and Isothermal Oxidation Behavior of Thermal Barrier Coatings (TBCs) with MCrAlY Bond Coat

Öz

Thermal barrier coatings (TBCs) are advanced protective coatings operating at elevated temperatures used to protect the fixed and movable parts of aero-engines and industrial gas turbine engines from environmental adverse effects. In the TBC system, the substrate material, metallic bonding and ceramic top coat materials used to protect against the major damage formation mechanisms such as oxidation and corrosion that may occur during service are the main elements that determine the life of the TBC system under usage conditions. In this study, NiCrAlY containing a metallic bonding coat and yttria stabilized zirconia (YSZ) coating were produced using atmospheric plasma spray (APS) coating method. The TBC system produced was subjected to isothermal oxidation tests at 1150 °C and at 5, 25 and 50 hours of time period. Scanning electron microscope (SEM) analysis was conducted before and after high temperature furnace tests in order to determine microstructural changes. The changes in the characteristics of the oxide structures formed in the metallic bonding and ceramic top coat interface structure based on time during the high temperature process have been studied and evaluated in detail. It has been observed that depending on the oxidation process, thermally grown oxide layer (TGO) structure is formed at the interface of the metallic bonding and ceramic top coat, and this layer, dependent on the increasing oxidation process, grows parabolically. It has been determined that the content and growth behavior of the TGO layer varies depending on the alloying elements in the bonding coat, except oxygen diffused from the surface to the interface.

Anahtar Kelimeler

• Isothermal oxidation
• atmospheric plasma spraying (APS)
• NiCrAlY
• yttria stabilized zirconia (YSZ)
• thermal barrier coating (TBC)

Kaynakça

1. [1] Sahith M.S., Giridhara G., Kumar R.S., “Development and analysis of thermal barrier coatings on gas turbine blades – A Review”, Materials Today:Proceedings, 5(1,3): 2746-2751, (2018).
2. [2] Izadinia M., Soltani R., Sohi M.H., “Effect of segmented cracks on TGO growth and life of thick thermal barrier coating under isothermal oxidation conditions”, Ceramics International, 46(6): 7475-7481, (2020).
3. [3] Padture N.P., Gell M., Jordan E.H., “Thermal barrier coatings for gas-turbine engine applications”, Science, 296(5566): 280-284, (2002).
4. [4] Goswami B., Ray A.K., Sahay S., “Thermal barrier coating system for gas turbine application-a review”, High Temperature materials and processes, 23(2): 73-92, (2004).
5. [5] Xu H., Guo H., Gong S., “Thermal barrier coatings in Developments in High Temperature Corrosion and Protection of Materials", Woodhead Publishing in Materials, Cambridge, 476-491, (2008).
6. [6] Akgün M., Demir H., “Optimization and finite element modelling of tool wear in milling of Inconel 625 superalloy”, Politeknik Dergisi, 24(2): 391-400, (2021).
7. [7] Coakley J., Whittaker M.T., Kolisnychenko S., “Ni-Based Superalloys”, Trans Tech Publications, Switzerland, (2020).
8. [8] Karaoglanli A.C., Ogawa K., Turk A., Ozdemir İ., “Thermal shock and cycling behavior of thermal barrier coatings (TBCs) used in gas turbines”, Progress in gas turbine performance, 237-260, (2013).

9. [9] Ozkan D., and Karaoglanli A.C., “High Entropy Alloys: production, properites and utilization areas”, El-Cezeri Journal of Science and Engineering, 8(1): 164-181, (2021).
10. [10] Liu D., Rinaldi C., Flewitt P.E.J., “Effect of substrate curvature on the evolution of microstructure and residual stresses in EBPVD-TBC”, Journal of the European Ceramic Society, 35(9): 2563-2575, (2015).
11. [11] Kilic M., Ozkan D., Gok M.S., Karaoglanli A.C., “Room-and High-Temperature Wear Resistance of MCrAlY Coatings Deposited by Detonation Gun (D-Gun) and Supersonic Plasma Spraying (SSPS) Techniques”, Coatings, 10(11): 1107, (2020).
12. [12] Karaoglanli A.C., and Turk A., “Isothermal oxidation behavior and kinetics of thermal barrier coatings produced by cold gas dynamic spray technique”, Surface and Coatings Technology, 318: 72-81, (2017).
13. [13] Thakare J.G., Pandey C., Mahapatra M.M., Mulik R.S., “Thermal barrier coatings—a state of the art review”, Metals and Materials International, 1-22, (2020).
14. [14] Karaoglanli A.C., Grund T., Turk A., Lampke T., “A comparative study of oxidation kinetics and thermal cyclic performance of thermal barrier coatings (TBCs)”, Surface and Coatings Technology, 371: 47-67, (2019).
15. [15] Clarke D., Levi C., “Materials design for the next generation thermal barrier coatings”, Annual Review of Materials Research, 33(1): 383-417, (2003).
16. [16] Ozgurluk Y., Doleker K.M., Ozkan, D., Ahlatci H., Karaoglanli, A.C., “Cyclic hot corrosion failure behaviors of EB-PVD TBC systems in the presence of sulfate and vanadate molten salts”, Coatings, 9(3), 166, (2019).
17. [17] Torkashvand K., Poursaeidi E., Mohammadi M., “Effect of TGO thickness on the thermal barrier coatings life under thermal shock and thermal cycle loading”, Ceramics International, 44(8): 9283-9293, (2018).
18. [18] Ahrens M., Vaßen R., Stöver D., “Stress distributions in plasma-sprayed thermal barrier coatings as a function of interface roughness and oxide scale thickness”, Surface and Coatings Technology, 161(1): 26-35, (2002).
19. [19] Karaoglanli A.C., “Effects of plastic deformation on isothermal oxidation behavior of CoNiCrAlY coatings”, Science of Advanced Materials, 7(1): 173-177, (2015).
20. [20] Shi P., Wang W., Wan S., Gao Q., Sun H., Feng X., Yi G., Xie E., Wang Q., “Tribological performance and high temperature oxidation behaviour of thermal sprayed Ni-and NiCrAlY-based composite coatings”, Surface and Coatings Technology, 405, 126615, (2021).
21. [21] Parlakyigit A.S., Ozkan, D., Oge M., Ozgurluk Y., Doleker K.M., Gulmez T., Karaoglanli, A.C., “Formation and growth behavior of TGO layer in TBCs with HVOF sprayed NiCr bond coat”, Emerging Materials Research, 9(2), 451-459, (2020).
22. [22] Takahashi R.J., Assis J.M.K., Neto F.P., Reis D.A.P., “Heat treatment for TGO growth on NiCrAlY for TBC application”, Materials Research Express, 6(12): 126442, (2020).
23. [23] Khakzadian J., Hosseini S.H., Zangeneh M.K., “Effect of substrate temperature on the oxidation behaviour of NiCrAlY Coating”, Surface Engineering, 37(1): 129-136, (2021).
24. [24] Doleker K., Ozgurluk Y., Parlakyigit A.S., Ozkan D., Gulmez T., Karaoglanli A.C., “Oxidation behavior of NiCr/YSZ thermal barrier coatings (TBCs)”, Open Chemistry, 16(1), 876-881, (2018).
25. [25] Gaskell D.R., Laughlin D.E., “Introduction to the Thermodynamics of Materials”, CRC press, 694, (2017).
26. [26] Doleker K.M., Ozgurluk Y., Ozkan D., Nihal M., Karaoglanli A.C., “Comparison of microstructures and oxidation behaviors of ytria and magnesia stabilized zirconia thermal barrier coatings (TBC)”, Materials and Technology, 52, 315-322, (2018).
27. [27] Shi J., Zhang T., Sun B., Wang B., Zhang X., Song L., “Isothermal oxidation and TGO growth behavior of NiCoCrAlY-YSZ thermal barrier coatings on a Ni-based superalloy”, Journal of Alloys and Compounds, 844, 156093, (2020).
28. [28] Puetz P., Huang X., Yang Q., Tang Z., “Transient oxide formation on APS NiCrAlY after oxidation heat treatment”, Journal of thermal spray technology, 20(3): 621-629, (2011).
29. [29] Dong H., Yang G.J., Li C.X., Luo, X.T., Li, C.J., “Effect of TGO thickness on thermal cyclic lifetime and failure mode of plasma‐sprayed TBCs”, Journal of the American Ceramic Society, 97(4): 1226-1232, (2014).
30. [30] Das S.M., Singh M.P., Chattopadhyay K., “Effect of Cr addition on the evolution of protective alumina scales and the oxidation properties of a Ta stabilized γ'-strengthened Co-Ni-Al-Mo-Ta-Ti alloy”, Corrosion Science, 172: 108683, (2020).
31. [31] Mahalingam S., Mohd Y.S., Manap A., Afandi N.M., Zainuddin R.A., Kadir N.F., “Crack propagation and effect of mixed oxides on TGO growth in thick La–Gd–YSZ thermal barrier Coating”, Coatings, 9(11), 719, (2019).
32. [32] Cen L., Qin W.Y., Yu Q.M., “On the role of TGO growth in the interface undulation in MCrAlY coating system upon thermal cycling”, Ceramics International, 45(17, Part B): 22802-22812, (2019).
33. [33] Hongyu Q., Xiaoguang Y., Yamei W., “Interfacial fracture toughness of APS bond coat/substrate under high temperature”, International journal of fracture, 157(1-2): 71-80, (2009).