Na2SO4-V2O5-NaCI Tuzuna Maruz Bırakılan Inconel 718 Süper Alaşım Malzemesinin Yüksek Sıcaklıkta Sıcak Korozyon Davranışı

Öz

Inconel 718 süper alaşımı, havacılık ve uzay endüstrisinde sıcak korozyona karşı dayanıklılığıyla bilinse de düşük kaliteli yakıtların neden olduğu agresif ortamlarda ciddi yapısal hasarlara maruz kalabilmektedir. Bu çalışmada, %35 Na2SO4 + %35 V2O5 + %30 NaCl tuz karışımı, Inconel 718 altlık üzerine uygulanarak 900 °C ± 25°C sıcaklıkta 1, 3, 5 ve 24 saatlik sıcak korozyon testleri gerçekleştirilmiştir. Test öncesi ve sonrası mikroyapısal değişimler SEM, EDS, elementel haritalama ve XRD ile analiz edilmiştir. Bulgular, kısa süreli maruziyetlerde sınırlı oksitlenme görülürken, 24 saatlik sürede yüzeyde belirgin faz dönüşümleri ve yapısal bozulmaların başladığını göstermiştir. Bu sonuç, Inconel 718’in yüksek sıcaklıkta agresif tuz ortamlarına karşı dayanımının zamanla azaldığını ortaya koymaktadır.

Anahtar Kelimeler

• süper alaşımlar
• tel erozyon yöntemi
• havacılık ve uzay endüstrisi
• termal bariyer kaplamalar

High-Temperature Hot Corrosion Behavior of Inconel 718 Superalloy Material Exposed to Na2SO4-V2O5-NaCI Salt

Abstract

Although Inconel 718 superalloy is known for its resistance to hot corrosion in the aerospace industry, it can be subjected to severe structural damage in aggressive environments caused by low-quality fuels. In this study, a 35% Na2SO4 + 35% V2O5 + 30% NaCl salt mixture was applied on an Inconel 718 substrate, and hot corrosion tests were performed at 900°C ± 25°C for 1, 3, 5, and 24 hours. Microstructural changes before and after the tests were analyzed by SEM, EDS, elemental mapping, and XRD. The results showed that while limited oxidation was observed in short-term exposures, significant phase transformations and structural deterioration started on the surface at 24 hours. This result reveals that the resistance of Inconel 718 to aggressive salt environments at high temperatures decreases over time.

Keywords

• Superalloys
• wire erosion method
• aerospace industry
• thermal barrier coatings

Kaynakça

1. Akdoğan V. U., Termal Bariyer Kaplamaların Lazer ile Yüzey Modifikasyonu, İstanbul Teknik Üniversitesi Fen Bilimleri Enstitüsü, Yüksek Lisans Tezi (Basılmış), 2011.
2. Alazzawi S., Mahmood W. A., Shihab S. K., Comparative Study of Natural Fiber-Reinforced Composites for Sustainable Thermal Insulation in Construction. International Journal of Thermofluids 24, 100839, 2024.
3. Altaf S. F., Rahman A., Wani M. F., Long-term stability and performance of nanostructured thermal barrier coatings deposited by magnetron sputtering on superalloys: A review. Surface Engineering 41(2), 149-175, 2025.
4. Badea T. A., Assessment of hot corrosion in molten Na2SO4 and V2O5 of inconel 625 fabricated by selective laser melting versus conventional technology. Materials 15(12), 4082, 2022.
5. Bayraktar Ş., Assessment of cutting performance on drilling with different drilling methods of fiber reinforced polymer composites: A Literature Review. Journal of the Faculty of Engineering and Architecture of Gazi University 33(2), 609-626, 2018.
6. Benito E. D., Ueno A., Fukuyama T., Current State of Knowledge on Bare High-Nickel Type Weathering Steel Towards the Application as Concrete Reinforcement. Journal of Advanced Concrete Technology 20(4), 313-327, 2022.
7. Binal G., Isothermal oxidation and hot corrosion behavior of HVOF sprayed 80Ni-20Cr coatings at 750° C. Surface and Coatings Technology 454, 129141, 2023.
8. Cinca N., Guilemany J. M., Thermal spraying of transition metal aluminides: An overview. Intermetallics, 24, 60-72, 2012.

9. Gupta A., Patel P., Shah S., Patel K., Nanocomposites in focus: tailoring drug delivery for enhanced therapeutic outcomes. Future Journal of Pharmaceutical Sciences 11(1), 37, 2025.
10. Hu S., Finklea H., Liu X., A Review of Molten Sulfate Salts Induced Hot Corrosion. Journal of Materials Science & Technology 90, 243-254, 2021.
11. Jeong W., Lee T., Youn S. J., Lee M., Kong T., Ryu H. J., Effect of decomposed TiCp on the mechanical properties of laser powder directed energy depositioned Inconel 718. Journal of Materials Science & Technology 224, 66-79, 2025.
12. Li L., Li L., Zhang G., Xue H., Cui M., Wang W., Liu D., Hot corrosion behavior of inconel 625 in Na2SO4 and V2O5 molten salt system. Metals 13(6), 1069, 2023.
13. Li Z., Lin X., Sui S., Zhao X., Yao B., Zhong C., Gasser A., Tan H., Single-crystal structure formation in laser directed energy deposited Inconel 718 through process parameter optimization and substrate orientation tuning. Journal of Materials Processing Technology 335, 118673, 2025.
14. Liu Z., Li R., Wu Y., Ye D., He C., Progress in terahertz nondestructive testing of thermal barrier coatings: a review. Nondestructive Testing and Evaluation 1-38, 2025.
15. Luo K., Li S., Xu G., Hosseini S. R. E., Lu, J., Hot corrosion behaviors of directed energy deposited Inconel 718/Haynes 25 functionally graded material at 700° C and 900° C. Corrosion Science 197, 110040, 2022.
16. Narayanan B. K., Duraiselvam M., Natarajan S., Khan M. A., Hot Corrosion and Oxidation Behaviour of a Laser Processed Nickel-based Superalloy. Lasers in Engineering (Old City Publishing) 43, 2019.
17. Odabas O., Karaoglanli A. C., Ozgurluk Y., Binal G., Ozkan, D., Evaluation of AlCoCrFeNiTi-high entropy alloy (HEA) as top coat material in thermal barrier coating (TBC) system and investigation of its high temperature oxidation behavior. Surface and Coatings Technology 495, 131569, 2025.
18. Odabas O, Karaoglanli A. C., Comparison of microstructural evolution and high temperature oxidation behavior of AlCoCrFeNiTi and AlCoCrFeNiZr high-entropy alloy coatings. Surface and Coatings Technology 494, 131529, 2024.
19. Patil A. R., Vagge S. T., Hot corrosion behaviour of Inconel 738 superalloy in presence of NaCl, Na2SO4, V2O5. Materials Today: Proceedings, 65, 74-80, 2022.
20. Pond Jr R. B, Shifler D. A, High-temperature corrosion-related failures. In: Failure Analysis and Prevention. ASM International 868-880, 2002.
21. Selim H., Suleiman B., Dawood A., Montagne P., Amancherla S., Khalidi A., Water-Based Yttrium Additive for Hot Corrosion Inhibition in a Gas Turbine. In: Turbo Expo: Power for Land, Sea, and Air. American Society of Mechanical Engineers, V03BT04A017, 2024.
22. Sun K., Zhong W., Huang S., He X., Cai W., Ma R., Jiang T., You S., Wang L., Li W., Research Progress on the Corrosion Mechanism and Protection Monitoring of Metal in Power Equipment. Coatings 15(2), 119, 2025.
23. Swaminathan J., Raghavan S., Iyer S. R., Studies on the hot corrosion of some nickel-base superalloys by vanadium pentoxide. Transactions of the Indian Institute of Metals (India), 46(3), 175-181, 1993.
24. Wang H., Guo Q., Li C., Cui L., Yao H., Liu Y., Effect of homogenization treatment on the microstructure and creep properties of additively manufactured Inconel 718 alloy modified by Ti2AlC inoculants. Journal of Alloys and Compounds 1017, 179062, 2025.
25. Yao B., Fu L., Zhu J., Yang W., Zhou L., Thermostable Nickel Chloride Film as High Specific Power Cathode for Thermal Battery. ACS Applied Materials & Interfaces 17(7), 10662-10673, 2025.