Effect of Co and Al Contents on Hot Corrosion Resistance of Powder Metallurgy Aeroengine Disk Superalloys

Abstract:

Hot corrosion behavior of a powder metallurgy superalloy (Alloy 1) in molten 95% Na₂SO₄+5%NaCl salts at 800 °C are investigated with average corrosion rate calculation, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy spectrum analyzer (EDS). Meanwhile, the hot corrosion tests of Alloy 2 at 800°C were also carried out for comparison. Experimental results show that the corrosion layers obtained after 100h of hot corrosion were mainly composed of Cr₂O₃, Al₂O₃ , NiO , Ni₃S₂ , NiCr₂O₄ and Cr₂S₃ at 800 °C. The cross-sectional morphologies and corresponding elemental maps indicate that a large amount of sulfides and oxides appeared in internal substrate. According to these results, the cooperating mechanism of oxidation and sulfuration in Na₂SO₄-NaCl salts for Alloy 1 is confirmed. Compared with Alloy 2, the increased Co and Al content in Alloy 1 with better hot corrosion resistance at 800 °C promoted the rapid formation of continuous Cr₂O₃ and Al₂O₃ protective films on the alloy surface in which Co inhibited internal oxidation of Al and reduced internal diffusion of S through the third element effect. Key words: powder metallurgy superalloy; hot corrosion; oxidation; molten Na₂SO₄-NaCl salts; sulfuration

• Periodical: Materials Science Forum (Volume 1072)
• Pages: 119-128
• DOI: https://doi.org/10.4028/p-00tbhr
• Online since: October 2022
• Authors: Wen Hui Yang*, Gao Feng Tian, De Lin Liu, Ren De Mu
• Keywords: Hot Corrosion, Molten Na₂SO₄- NaCl Salts, Oxidation, Powder Metallurgy Superalloy, Sulfuration

References

[1] HE Jia-hua, GUO xi-ping, QIAO Yan-qiang. Oxidation and hot corrosion behaviors of Nb-Si based ultrahigh temperature alloys at 900℃[J]. Transactions of Nonferrous Metals Society of China, 2021, 31: 207-210.

DOI: 10.1016/s1003-6326(20)65488-7

[2] MENG Jun-sheng, CHEN Ming-xuan, SHI Xiao-ping, et al. Transactions of Nonferrous Metals Society of China [J]. 2021,31: 2402-2414.

[3] WU Yu-xiao, ZHANG Heng, LI Fu-lin, et al. Kinetics and microstructural evolution during recrystallization of a Ni3Al-based single crystal superalloy [J]. Transactions of Nonferrous Metals Society of China, 2012, 22: 2098-2105.

DOI: 10.1016/s1003-6326(11)61434-9

[4] ZHOU Peng-jie, YU Jin-jiang, SUN Xiao-feng, et al. Roles of Zr and Y in cast microstructure of M951 nickel-based superalloy [J]. Transactions of Nonferrous Metals Society of China, 2012, 22: 1594-1598.

DOI: 10.1016/s1003-6326(11)61361-7

[5] MENG Jun-sheng, JI Ze-sheng. Effect of different fillers on oxidation behavior of low-temperature chromizing coating [J]. Transactions of Nonferrous Metals Society of China, 2014, 24: 1785-1790.

DOI: 10.1016/s1003-6326(14)63254-4

[6] STRINGER J. Hot corrosion of high-temperature alloys. Annual Revies of Materials Science 1977;7: 477-509.

[7] WOOD G C. Stott F H. Directions for future research in high-temperature corrosion. Oxid [J]. Met 1995;44(1/2): 375-397.

DOI: 10.1007/bf01046733

[8] PARK S J, SEO S M, YOO Y S, et al. Effects of Cr, W, and Mo on the high temperature oxidation of Ni-based superalloys [J]. Materials, 2019, 12: 2934.

DOI: 10.3390/ma12182934

[9] PEDRAZZINI S, CHILD D J, WEST G, et al. Oxidation behavior of a next generation polycrystalline Mn containing Ni-based superalloy [J]. Scripta Materialia, 2016, 113: 51-54.

DOI: 10.1016/j.scriptamat.2015.10.001

[10] CHOI S C, CHO H J, LEE D B. Effect of Cr, Co, and Ti additions on the high-temperature oxidation behavior of Ni3Al [J]. Oxidation of Metals, 1996, 46: 109-127.

DOI: 10.1007/bf01046886

[11] WEISER M, GALETZ M C, CHATER R J, et al. Growth mechanisms of oxide scales on two-phase Co/Ni-base model alloys between 800℃ and 900℃ [J]. Journal of The Electrochemical Society, 2020, 167: 021504.

DOI: 10.1149/1945-7111/ab69f7

[12] ISMAIL F B, VORONTSOV V A, LINDLEY T C. Alloying effects on oxidation mechanisms in polycrystalline Co–Ni base superalloys [J]. Corrosion Science, 2017, 116: 44-52.

DOI: 10.1016/j.corsci.2016.12.009

[13] QIAO Min, ZHOU Chun-gen. Hot corrosion behavior of Co modified NiAl coating on nickel base superalloys [J]. Corrosion Science, 2012, 63: 239-245.

DOI: 10.1016/j.corsci.2012.06.027

[14] FAN Q X, JIANG S M, WU D L, et al. Preparation and hot corrosion behaviour of two Co modified NiAl coatings on a Ni-based superalloy [J]. Corrosion Science, 2013, 76: 373-381.

DOI: 10.1016/j.corsci.2013.07.008

[15] Gonzalez-Rodriguez J G, Haro S, Martinez-Villafane A. Porcayo-Calderon J. Corrosion performance of heat resistant alloys in Na2SO4-V2O5 molten salts. Mater Sci Eng A 2006, 435: 258-265.

DOI: 10.1016/j.msea.2006.06.138

[16] Uusitalo MA, Vuoristo PMJ, Maantyla TA. High temperature corrosion of coatings and boiler steels below chlorine-containing salt deposits. Corros Sci 2004, 46:1311-1331.

DOI: 10.1016/j.corsci.2003.09.026

[17] Li J, Wang H M. Microstructure and mechanical properties of rapid directionally solidified Ni-base superalloy Rene41 by laser melting deposition manufacturing. Mater Sci Eng A 2010, 527:4823-4829.

DOI: 10.1016/j.msea.2010.04.062

[18] Liu L, Li Y, Wang F H. Influence of micro-structure on corrosion behavior of a Ni-based superalloy in 3.5% NaCl. Electrochim Acta 2007, 52:7193-7202.

DOI: 10.1016/j.electacta.2007.05.043

[19] HUANG Shuo, W ANG Lei, HUANG Yan, LI Jun-tao. High temperature hot corrosion behaviors of directional solidification Ni-base superalloy DZ792 and DZ792G[J]. Journal of Northeastern University, 2013, 34(11): 1580−1584.

[20] GOWARD G. Protective coatings-purpose, role, and design [J]. Material Science Engineering, 1986, 2: 194-200.

[21] NIU Y, ZHANG X J, WU Y, GESMUNDO F. The third-element effect in the oxidation of Ni-xCr-7Al (x = 0, 5, 10, 15 at. %) alloys in 1 atm O2 at 900-1000℃[J]. Corrosion Science, 2006, 48: 4020-4036.

DOI: 10.1016/j.corsci.2006.03.008

[22] J. Engkvist, U. Bexell, M. Grehk, et al, High temperature oxidation of FeCrAl-alloys - Influence of Al-concentration on oxide layer characteristics [J]. Mater. Corros 2009, 60: 876-881.

DOI: 10.1002/maco.200805186