Iridium is one of the rarest and most corrosion-resistant metals known, belonging to the platinum group. Discovered in 1803 by Smithson Tennant, it is renowned for its silvery-white luster, extreme hardness, and chemical inertness. With a melting point of 2454 °C and remarkable thermal and mechanical stability, iridium plays a crucial role in high-temperature, high-stress, and chemically aggressive environments.
Material Overview
Iridium crystallizes in a face-centered cubic (FCC) structure with a density of 22.56 g·cm?³, making it one of the densest elements. It retains strength even above 2000 °C and exhibits outstanding resistance to most acids, including aqua regia, due to its low reactivity and strong metallic bonding. Weiland et al. (2006) reported that iridium maintains structural integrity and creep resistance up to 2300 °C, outperforming platinum and rhodium in mechanical and oxidation tests. Merker et al. (2007) observed that fine-grained microstructures improve iridium’s ductility and mitigate creep anomalies at high service temperatures. Wu et al. (2013) confirmed that iridium coatings are among the best oxidation barriers for refractory metals above 1800 °C, owing to their chemical stability and low oxygen permeability. More recently, Chanda (2025) highlighted iridium’s expanding role in superalloys and catalysis, noting advances in powder metallurgy and microstructural control that enable new high-strength, oxidation-resistant composites.
Applications and Advantages
Iridium is used extensively in spark plugs, crucibles for crystal growth, high-temperature furnace components, and electrodes for electrochemical systems. Its combination of high melting point, corrosion resistance, and low vapor pressure makes it ideal for aerospace, nuclear, and semiconductor technologies. Iridium-based alloys are increasingly employed in turbine engines, thermocouples, and space propulsion systems, where material integrity under extreme heat and radiation is essential. Furthermore, biomedical applications—including cancer treatment and implant coatings—are emerging due to its inertness and biocompatibility. Patented Ir–Rh–La–Y–Zr composite metals (Hu, 2017) demonstrate improved toughness and oxidation resistance, paving the way for multifunctional iridium-based materials for both industrial and medical use.
Goodfellow Availability
Goodfellow supplies Iridium (Ir) in research-grade purity for demanding high-temperature, catalytic, and electronic applications. Available in wire, foil, and powder forms, each product undergoes rigorous refining to ensure uniform composition and surface integrity. Custom dimensions and specialized processing options are available upon request to meet unique research and engineering specifications.
Explore Iridium (Ir) and other advanced materials in Goodfellow’s online catalogue: Goodfellow product finder.
References
- Weiland, R., Lupton, D. F., Fischer, B., Merker, J., Scheckenbach, C., & Witte, J. (2006). High-temperature mechanical properties of the platinum group metals. Platinum Metals Review, 50(4), 182–192. https://doi.org/10.1595/147106706X154198
- Merker, J., Fischer, B., Lupton, D. F., & Witte, J. (2007). Investigations on structure and high temperature properties of iridium. Materials Science Forum, 539–543, 2216–2221. https://doi.org/10.4028/WWW.SCIENTIFIC.NET/MSF.539-543.2216
- Wu, W., Chen, Z., Cong, X., & Wang, L. (2013). Review on high-temperature oxidation-resistant iridium coating for refractory metals. Rare Metal Materials and Engineering, 42(3), 485–491.
- Hu, X. (2017). High-temperature resistant and thermogalvanic corrosion resistant composite metal product. Patent.
- Chanda, A. (2025). Iridium base refractory superalloys. Materials Research Foundations.