Evaluating the Corrosion Resistance of Inconel 625 Coatings, Processed by Compact Plasma Spray, for Applications in Concentrating Solar Power Plants

Abstract:

Thermal energy storage (TES) systems have paramount importance in the design of Concentrating Solar Power (CSP) plants. TES systems allow storing the energy collected from solar radiation as heat energy in a thermal fluid and, in that way, extending the energy duration period of the plant and making the produced electricity dispatchable, depending on the actual demand and not only on the availability of the sun. The thermal fluids, synthetic oils, or molten salts, usually operate at temperatures from 500°C up to 800°C. The harsh operative conditions bring out issues related to the compatibility with the construction materials of CSP components, i.e., carbon and stainless steel. Coating of low-alloy structural steel with high-resistant materials has been addressed as a promising solution for mitigating the corrosion in TES system components. Compact plasma spray process was used to deposit Inconel 625 alloy onto T22 carbon steel coupons. Nitrate salts mixture, 60%NaNO₃-40KNO₃, commonly employed in CSP systems as operative and thermal storage fluid was used as corrosion medium. The tests were conducted by immersing coated and uncoated samples in molten salts at 500°C for 1, 3 7, and 14 days to assess the corrosion behavior of the In625 coatings. After 24 hours of exposition to molten nitrate salts, the T22 surface showed a pronounced oxidized layer having a thickness of approximately 20 µm. This layer is mainly composed of oxygen, iron, and chromium, which are the main constituents of carbon steel, with a few traces of sodium and potassium derived from the reaction of salts with the steel. Inconel 625, on the other hand, showed the formation of very thin scales of corrosion products localized only on the surface of the sample. Longer exposition is expected to produce a more pronounced degradation of uncoated steel, but barely affect the Inconel 625 coating

• Periodical: Key Engineering Materials (Volume 926)
• Pages: 1736-1745
• DOI: https://doi.org/10.4028/p-d3uuc2
• Online since: July 2022
• Authors: Felice Rubino*, David Merino, Claudio Munez, Pedro Poza
• Keywords: Coating, Compact Plasma Spray, Corrosion Protection, Molten Salts, Thermal Energy Storage

References

[1] F. Rovense, M. Perez, M. Amelio, V. Ferraro, N. Scornaienchi, Feasibility analysis of a solar field for a closed unfired Joule-Brayton cycle, Int J Heat Technol 35 (2017) 166–71.

DOI: 10.18280/ijht.35sp0123

[2] F. Rovense, M.Á. Reyes-Belmonte, M. Romero, J. González-Aguilar, Thermo-economic analysis of a particle-based multi-tower solar power plant using unfired combined cycle for evening peak power generation, Energy 240 (2022) 122798.

DOI: 10.1016/j.energy.2021.122798

[3] M. Walczak, F. Pineda, Á.G. Fernández, C. Mata-Torres, R.A. Escobar, Materials corrosion for thermal energy storage systems in concentrated solar power plants, Renew Sustain Energy Rev 86 (2018) 22–44.

DOI: 10.1016/j.rser.2018.01.010

[4] M. Sarvghad, S. Delkasar Maher, D. Collard, M. Tassan, G. Will, T.A. Steinberg, Materials compatibility for the next generation of Concentrated Solar Power plants, Energy Storage Mater 14 (2018)179–98.

DOI: 10.1016/j.ensm.2018.02.023

[5] S. Bell, T. Steinberg, G.Will, Corrosion mechanisms in molten salt thermal energy storage for concentrating solar power, Renew. Sustain. Energy Rev. 114 (2019)109328.

DOI: 10.1016/j.rser.2019.109328

[6] M.T. Islam, N. Huda, A.B. Abdullah, R.Saidur, A comprehensive review of state-of-the-art concentrating solar power (CSP) technologies Current status and research trends, Renew Sustain Energy Rev 91 (2018) 987–1018.

DOI: 10.1016/j.rser.2018.04.097

[7] K. Vignarooban, X. Xu, A. Arvay, K. Hsu, A.M. Kannan, Heat transfer fluids for concentrating solar power systems – A review, Appl Energy 146 (2015) 383–96.

DOI: 10.1016/j.apenergy.2015.01.125

[8] S. Goods, R. Bradshaw, M. Prairie, J. Chavez, Corrosion of stainless and carbon steels in molten mixtures of industrial nitrates. Sandia National Lab, Livermore, CA (United States) (1994).

DOI: 10.2172/10141843

[9] A.G. Fernández, H. Galleguillos, E. Fuentealba, F.J. Pérez, Corrosion of stainless steels and low-Cr steel in molten Ca(NO3)2–NaNO3–KNO3 eutectic salt for direct energy storage in CSP plants, Sol Energy Mater Sol Cells 141 (2015) 7–13.

DOI: 10.1016/j.solmat.2015.05.004

[10] A.G. Fernández, M. Cortes, E. Fuentealba, F.J. Pérez, Corrosion properties of a ternary nitrate/nitrite molten salt in concentrated solar technology, Renew Energy 80 (2015) 177–83.

DOI: 10.1016/j.renene.2015.01.072

[11] M. Gonzalez, U. Nithiyanantham, E. Carbó-Argibay, O. Bondarchuk, Y. Grosu, A. Faik, Graphitization as efficient inhibitor of the carbon steel corrosion by molten binary nitrate salt for thermal energy storage at concentrated solar power, Sol Energy Mater Sol Cells 203 (2019) 110172.

DOI: 10.1016/j.solmat.2019.110172

[12] W. Ding, A. Bonk, J. Gussone, T. Bauer, Electrochemical measurement of corrosive impurities in molten chlorides for thermal energy storage, J Energy Storage 15 (2018) 408–14.

DOI: 10.1016/j.est.2017.12.007

[13] H. Singh, D. Puri, S. Prakash, T.K. Ghosh, Hot corrosion of a plasma sprayed Ni3Al coating on a Ni-base superalloy, Mater Corros 58 (2007) 857–66.

DOI: 10.1002/maco.200704072

[14] A. Agüero, F.J. García de Blas, M.C. García, R. Muelas, A. Román, Thermal spray coatings for molten carbonate fuel cells separator plates, Surf Coatings Technol 146–147 (2001) 578–85.

DOI: 10.1016/s0257-8972(01)01435-9

[15] A. Agüero, Progress in the development of coatings for protection of new generation steam plant components, Energy Mater 3 (2008) 35–44.

DOI: 10.1179/174892407x248554

[16] A. Astarita, S. Genna, C. Leone, F.M.C. Minutolo, F. Rubino, A. Squillace, Study of the Laser Remelting of a Cold Sprayed Titanium Layer, Procedia CIRP 33 (2015) 452–7.

DOI: 10.1016/j.procir.2015.06.101

[17] F. Rubino, P. Ammendola, A. Astarita, F. Raganati, A. Squillace, A. Viscusi, et al. An Innovative Method to Produce Metal Foam Using Cold Gas Dynamic Spray Process Assisted by Fluidized Bed Mixing of Precursors, Key Eng Mater 651–653 (2015) 913–8.

DOI: 10.4028/www.scientific.net/kem.651-653.913

[18] V. Paradiso, F. Rubino, F. Tucci, A. Astarita, P. Carlone, Thermo-mechanical modeling of laser treatment on titanium cold-spray coatings, AIP Conf. Proc. 1960 (2018) 100011.

DOI: 10.1063/1.5034951

[19] F. Rubino, A. Astarita, P. Carlone, S. Genna, C. Leone, F. Memola Capece Minutolo, et al. Selective Laser Post-Treatment on Titanium Cold Spray Coatings, Mater Manuf Process 31 (2016) 1500–6.

DOI: 10.1080/10426914.2015.1037912

[20] F. Rubino, V. Paradiso, A. Astarita, P. Carlone, A. Squillace, Advances in Titanium on Aluminium Alloys Cold Spray Coatings, in: P. Cavaliere (Eds.), Cold-Spray Coatings, Springer International Publishing, Cham, 2018, p.225–49.

DOI: 10.1007/978-3-319-67183-3_7

[21] A. Viscusi, A. Astarita, R. Della Gatta, F. Rubino, A perspective review on the bonding mechanisms in cold gas dynamic spray, Surf Eng 35 (2019) 743–71.

DOI: 10.1080/02670844.2018.1551768

[22] J. Porcayo-Calderon, O. Sotelo-Mazon, V.M. Salinas-Bravo, C.D. Arrieta-Gonzalez, J.J. Ramos-Hernandez, C. Cuevas-Arteaga, Electrochemical Performance of Ni20Cr coatings applied by combustion powder spray in ZnCl2-KCl molten salts, Int J Electrochem Sci 7 (2012) 1134–48.

[23] J. Porcayo-Calderón, O. Sotelo-Mazón, M. Casales-Diaz, J.A. Ascencio-Gutierrez, V.M. Salinas-Bravo, L. Martinez-Gomez, Electrochemical study of Ni20Cr coatings applied by HVOF Process in ZnCl2-KCl at high temperatures, J Anal Methods Chem 2014 (2014) 503618.

DOI: 10.1155/2014/503618

[24] A.J.L. Marulanda, Corrosión en sales fundidas de un acero recubierto mediante rociado térmico por llama, Prospectiva 12 (2014 ) 15.

DOI: 10.15665/rp.v12i1.146

[25] J.C. Gomez-Vidal, Corrosion resistance of MCrAlX coatings in a molten chloride for thermal storage in concentrating solar power applications, Npj Mater Degrad 1 (2017) 1–8.

DOI: 10.1038/s41529-017-0012-3

[26] J.C. Gomez-Vidal, J. Noel, J. Weber, Corrosion evaluation of alloys and MCrAlX coatings in molten carbonates for thermal solar applications, Sol Energy Mater Sol Cells 157 (2016) 517–25.

DOI: 10.1016/j.solmat.2016.07.029

[27] S.S. Raiman, R.T. Mayes, J.M. Kurley, R. Parrish, E. Vogli, Amorphous and partially-amorphous metal coatings for corrosion resistance in molten chloride salt, Sol Energy Mater Sol Cells 201 (2019) 110028.

DOI: 10.1016/j.solmat.2019.110028

[28] F. Rubino, P. Poza, G. Pasquino, P. Carlone, Thermal Spray Processes in Concentrating Solar Power Technology, Metals 11 (2021) 1377.

DOI: 10.3390/met11091377

[29] A. Rico, A. Salazar, M.E. Escobar, J. Rodriguez, P. Poza, Optimization of atmospheric low-power plasma spraying process parameters of Al2O3-50wt%Cr2O3 coatings, Surf Coatings Technol 354 (2018) 281–96.

DOI: 10.1016/j.surfcoat.2018.09.032

[30] A. Soleimani Dorcheh, R.N. Durham, M.C. Galetz, Corrosion behavior of stainless and low-chromium steels and IN625 in molten nitrate salts at 600 °C, Sol Energy Mater Sol Cells 144 (2016) 109–16.

DOI: 10.1016/j.solmat.2015.08.011

[31] A.G. Fernández, M.I. Lasanta, F.J. Pérez, Molten Salt Corrosion of Stainless Steels and Low-Cr Steel in CSP Plants, Oxid Met 78 (2012) 329–48.

DOI: 10.1007/s11085-012-9310-x

[32] X. Ou, Z. Sun, M. Sun, D. Zou, Hot-corrosion mechanism of Ni-Cr coatings at 650°C under different simulated corrosion conditions, J China Univ Min Technol 18 (2008) 444–8.

DOI: 10.1016/s1006-1266(08)60092-9