Iridium Base Refractory Superalloys
Ayanna Chanda, Leena Vij, Arti Jain
Iridium, a frequently overlooked metal, has emerged as a transformative force grasping onto the reins of high-temperature refractory superalloys. This chapter delves into the history, properties, manufacturing processes, and applications of iridium-based superalloys. Iridium’s exceptional physical properties and corrosion resistance, coupled with its microstructure, has carved an exceptional place within the sphere of heat-resistant materials. Conventional techniques such as melting, purification and welding, alongside novel ones like powder metallurgy and deformation processing, have contributed to the manufacture of alloys with diverse applications. These range from aerospace to energy-related technologies, such as gas turbine engines, spark plugs, electrocatalysts, to emerging biomedical applications such as coronary stents and cancer treatment. Despite challenges such as brittleness, high cost and limited availability, the locked potential of this metal as an alloy is immense. Addressing these challenges and exploring newer combinations with other metals will further enhance the prospects. The future of Iridium based technology are endless, with the potential to be a driving force to drive economic growth and advance renewable energy solutions.
Keywords
High-Temperature, Microstructure, Corrosion Resistance, Aerospace, Melting
Published online 9/10/2025, 14 pages
Citation: Ayanna Chanda, Leena Vij, Arti Jain, Iridium Base Refractory Superalloys, Materials Research Foundations, Vol. 178, pp 81-94, 2025
DOI: https://doi.org/10.21741/9781644903698-5
Part of the book on Superalloys
References
[1] H.A. Kishawy, A. Hosseini, Superalloys BT- machining difficult-to-cut materials: basic principles and challenges, in: H.A. Kishawy, A. Hosseini (Eds.), Springer International Publishing, Cham, 2019: pp. 97–137. https://doi.org/10.1007/978-3-319-95966-5_4
[2] D.B. Miracle, M.H. Tsai, O.N. Senkov, V. Soni, R. Banerjee, Refractory high entropy superalloys (RSAs), Scr. Mater. 187 (2020) 445–452. https://doi.org/https://doi.org/10.1016/j.scriptamat.2020.06.048
[3] I. Razumovskii, B. Bokstein, M. Razumovsky, Approaches to the development of advanced alloys based on refractory metals, Encyclopedia 3 (2023) 311–326. https://doi.org/10.3390/encyclopedia3010019
[4] S. Allard, Metals: Thermal and mechanical data, Elsevier, 2013.
[5] Y. Yamabe-Mitarai, Y.F. Gu, H. Harada, Two-phase iridium-based refractory superalloys, Platin. Met. Rev. 46 (2002) 74–81.
[6] E.K. Ohriner, Processing of iridium and iridium alloys, Platin. Met. Rev. 52 (2008) 186–197. https://doi.org/10.1595/147106708X333827
[7] L.B. Hunt, A history of iridium, Platin. Met. Rev. 31 (1987) 32–41.
[8] G. Xu, X. Chong, Y. Zhou, Y. Wei, C. Hu, A. Zhang, R. Zhou, J. Feng, Effects of the alloying element on the stacking fault energies of dilute Ir-based superalloys: A comprehensive first-principles study, J. Mater. Res. 35 (2020) 2718–2725.
[9] J. Merker, B. Fischer, D.F. Lupton, J. Witte, Investigations on structure and high temperature properties of iridium, in: Mater. Sci. Forum, Trans Tech Publ, 2007: pp. 2216–2221.
[10] J. Emsley, Nature’s building blocks: an AZ guide to the elements, Oxford University Press, USA, 2011.
[11] K.P. Kühn, I.F. Chaberny, K. Massholder, M. Stickler, V.W. Benz, H.G. Sonntag, L. Erdinger, Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UVA light, Chemosphere 53 (2003) 71–77. https://doi.org/10.1016/S0045-6535(03)00362-X
[12] Iridium, (n.d.). https://www.scientificlib.com/en/Chemistry/Elements/Iridium.html (accessed July 26, 2024).
[13] K.J. Kurzydlowski, B. Ralph, The quantitative description of the microstructure of materials, CRC press, 1995.
[14] G. Liu, L. Kong, S. Ruan, S. Birosca, Microstructure and phases structure in nickel-based superalloy IN713C after solidification, Mater. Charact. 182 (2021) 111566. https://doi.org/https://doi.org/10.1016/j.matchar.2021.111566
[15] B. Gwalani, D. Choudhuri, K. Liu, J.T. Lloyd, R.S. Mishra, R. Banerjee, Interplay between single phase solid solution strengthening and multi-phase strengthening in the same high entropy alloy, Mater. Sci. Eng. A 771 (2020) 138620. https://doi.org/https://doi.org/10.1016/j.msea.2019.138620
[16] S.J. Barnes, M.L. Fiorentini, Iridium, ruthenium and rhodium in komatiites: Evidence for iridium alloy saturation, Chem. Geol. 257 (2008) 44–58. https://doi.org/10.1016/J.CHEMGEO.2008.08.015
[17] J.B. Sha, Y. Yamabe-Mitarai, Saturated solid-solution hardening behavior of Ir–Hf–Nb refractory superalloys for ultra-high temperature applications, Scr. Mater. 54 (2006) 115–119. https://doi.org/https://doi.org/10.1016/j.scriptamat.2005.08.038
[18] X. Fang, R. Hu, J. Yang, Y. Liu, M. Wen, Microstructure evolution and mechanical properties of novel γ/γ′ two-phase strengthened Ir-based superalloys, Metals (Basel). 9 (2019) 1171.
[19] Y. Liu, C.T. Liu, L. Heatherly, E.P. George, Effects of alloying elements on dendritic segregation in iridium alloys, J. Alloys Compd. 459 (2008) 130–134. https://doi.org/10.1016/J.JALLCOM.2007.04.252
[20] E.K. Ohriner, Purification of iridium by electron beam melting, J. Alloys Compd. 461 (2008) 633–640. https://doi.org/10.1016/J.JALLCOM.2007.07.067
[21] Z. Mao, W. Xian, G. Qin-Qin, H. Chang-Yi, Z. Jun, C. Hong-Zhong, Z. Gui-Xue, W. Xing-Qiang, Z. Xu-Xiang, W. Yan, Optimization of process parameters for hot isostatic pressing of Ir–Rh alloys based on first-principles calculations, Mater. Res. Express 9 (2022) 116513. https://doi.org/10.1088/2053-1591/AC9887
[22] C. Xiang, H. Liu, Y. Huang, H. Tang, Preparation and microstructure of Ir-Zr-W alloys by powder metallurgy route, Rare Met. Mater. Eng. 38 (2009) 1132–1135. https://doi.org/10.1016/S1875-5372(10)60042-2
[23] P. Panfilov, A. Yermakov, O. V. Antonova, V.P. Pilyugin, Plastic deformation of polycrystalline iridium at room temperature, Platin. Met. Rev. 53 (2009) 138–146. https://doi.org/10.1595/147106709X463318
[24] Z. Amirsardari, Y. Vahidshad, M.A. Amirifar, A.H. Khodabakhshi, A. Dourani, N. Ghadiri Massoom, Method for preventing the contamination of iridium nanocatalyst during plasma arc welding procedure, J. Fail. Anal. Prev. 21 (2021) 1289–1296. https://doi.org/10.1007/S11668-021-01165-Z/FIGURES/9
[25] J.R. Handley, Increasing applications for iridium, Platin. Met. Rev. 30 (1986) 12–13. https://doi.org/10.1595/003214086X3011213
[26] W.P. Wu, Z.F. Chen, Iridium coating: processes, properties and application, Part I: Processes for protection in high-temperature environments against oxidation and corrosion, Johnson Matthey Technol. Rev. 61 (2017) 16–28. https://doi.org/10.1595/205651317X693606/CITE/REFWORKS
[27] H. Osamura, N. Abe, Development of New Iridium Alloy for Spark Plug Electrodes, SAE Tech. Pap. (1999). https://doi.org/10.4271/1999-01-0796
[28] J.R. Yang, X. Fang, Y. Liu, Z.-T. Gao, M. Wen, R. Hu, Microstructure evolution and mechanical properties of a novel γ′ phase-strengthened Ir-W-Al-Th superalloy, Rare Met. 40 (2021) 3588–3597. https://doi.org/10.1007/s12598-020-01682-0
[29] S.A. David, R.G. Miller, Z. Feng, Welding of unique and advanced alloys for space and high-temperature applications: welding and weldability of iridium and platinum alloys†, Sci. Technol. Weld. Join. 22 (2017) 244–256. https://doi.org/10.1080/13621718.2016.1222255
[30] B.D. Reed, J.A. Biaglow, S.J. Schneider, Iridium-coated rhenium radiation-cooled rockets, (1997).
[31] B. Huang, Y. Zhao, Iridium-based electrocatalysts toward sustainable energy conversion, EcoMat 4 (2022) e12176. https://doi.org/10.1002/EOM2.12176
[32] N. Muhammad, D. Whitehead, A. Boor, W. Oppenlander, Z. Liu, L. Li, Picosecond laser micromachining of nitinol and platinum–iridium alloy for coronary stent applications, Springer 106 (2012) 607–617. https://doi.org/10.1007/s00339-011-6609-4
[33] F. Wang, K. Kusada, D. Wu, T. Yamamoto, T. Toriyama, S. Matsumura, Y. Nanba, M. Koyama, H. Kitagawa, Solid-solution alloy nanoparticles of the immiscible iridium–copper system with a wide composition range for enhanced electrocatalytic applications, Angew. Chemie Int. Ed. 57 (2018) 4505–4509. https://doi.org/10.1002/ANIE.201800650
[34] R. Paudel, S. KC, S. Adhikari, J.C. Zhu, S. Ahmad, G. Chandra Kaphle, D. Paudyal, Electronic and magnetic properties of iridium-based novel Heusler alloys, J. Magn. Magn. Mater. 555 (2022) 169405. https://doi.org/10.1016/J.JMMM.2022.169405
[35] J. Fischer, Effect of small additions of Ir on properties of a binary Au–Ti alloy, Dent. Mater. 18 (2002) 331–335. https://doi.org/10.1016/S0109-5641(01)00058-6
[36] X.Y. Zhu, J.J. Wei, L.X. Chen, J.L. Liu, L.F. Hei, C.M. Li, Y. Zhang, Anti-sticking Re-Ir coating for glass molding process, Thin Solid Films 584 (2015) 305–309. https://doi.org/10.1016/J.TSF.2015.01.002
[37] Fukushima, Amorphous alloy, molding die, and method for producing optical element, (2013).
[38] V. Ramesh, J. Johny, J. Jakobi, R. Stuckert, C. Rehbock, S. Barcikowski, Platinum-iridium alloy nanoparticle coatings produced by electrophoretic deposition reduce impedance in 3D neural electrodes, ChemPhysChem 25 (2024) e202300623. https://doi.org/10.1002/CPHC.202300623
[39] A. Yu, S. Moon, T. Kwon, Y. Bin Cho, M.H. Kim, C. Lee, Y. Lee, Au-Ir alloy nanofibers synthesized from Au-Ir/IrO2 composites via thermal hydrogen treatment: Application for glucose oxidation, sensors and actuators. B Chem. 310 (2020) 127822. https://doi.org/10.1016/J.SNB.2020.127822
[40] X. Xiong, J. Tang, Y. Ji, W. Xue, H. Wang, C. Liu, H. Zeng, Y. Dai, H.J. Peng, T. Zheng, C. Xia, X. Liu, Q. Jiang, High-efficiency iridium-yttrium alloy catalyst for acidic water electrolysis, Adv. Energy Mater. 14 (2024) 2304479. https://doi.org/10.1002/AENM.202304479
[41] K. Hubkowska, M. Pająk, A. Czerwiński, The effect of the iridium alloying and hydrogen sorption on the physicochemical and electrochemical properties of palladium, Mater. 2023, Vol. 16, Page 4556 16 (2023) 4556. https://doi.org/10.3390/MA16134556
[42] L. Yang, J. Huang, S. Dai, X. Tang, Z. Hu, M. Li, H. Zeng, R. Luque, P. Duan, Z. Rui, Uniphase ruthenium–iridium alloy-based electronic regulation for electronic structure–function study in methane oxidation to methanol, J. Mater. Chem. A 8 (2020) 24024–24030. https://doi.org/10.1039/D0TA08350J
[43] Y. Zhang, J. Guo, J. Ding, C. Li, Q. Zhao, A flow-through ti4o7 membrane electrode for ballast water treatment: performance, mechanism, and comparison with ru-ir electrode, (2024). https://doi.org/10.2139/SSRN.4776968
[44] D.B. Miracle, M.H. Tsai, O.N. Senkov, V. Soni, R. Banerjee, Refractory high entropy superalloys (RSAs), Scr. Mater. 187 (2020) 445–452. https://doi.org/10.1016/J.SCRIPTAMAT.2020.06.048
[45] National Center for Biotechnology Information, Melting point in the periodic table of elements. https://pubchem.ncbi.nlm.nih.gov/ptable/melting-point/2024 (accessed September 16, 2024).
[46] National Center for Biotechnology Information, Density in the periodic table of elements. https://pubchem.ncbi.nlm.nih.gov/periodic-table/density/2024 (accessed September 16, 2024).
[47] Iridium Prices– Historical Graph [Realtime Updates]. https://procurementtactics.com/iridium-prices/ (accessed September 17, 2024).
[48] Iridium demand worldwide 2024 | Statista, (n.d.). https://www.statista.com/statistics/585840/demand-for-iridium-worldwide/2024 (accessed September 17, 2024).
[49] I. Iavicoli, V. Leso, Iridium, Handb. Toxicol. Met. Fifth Ed. 2 (2022) 369–390. https://doi.org/10.1016/B978-0-12-822946-0.00015-5
