Platinum-Iridium Spooled Wire (Pt75-Ir25)

Platinum/Iridium Alloy Spooled Wire (Pt75/Ir25) sits toward the higher end of the platinum-iridium series, with 25% iridium content delivering a Vickers hardness of 230–240, tensile strength of 860–1500 MPa, and elastic modulus of 218–220 GPa — all substantially higher than the lower-iridium grades. The alloy is supplied in the annealed condition, which moderates the reduction in ductility associated with higher iridium loadings and preserves the elongation at break needed for precision forming operations, while electrical resistivity of 31–32 µΩ·cm and a low temperature coefficient reflect the more iridium-influenced alloy character. Peer-reviewed research confirms that ductility decreases with increasing iridium content across the Pt-Ir series due to enhanced interatomic interactions, and the annealed supply condition for this grade acknowledges and mitigates this effect. Its chemical inertness, high density, and biocompatibility — well-documented in neural electrode literature including cochlear implant and cortical stimulation studies — support its use in precision surgical tools, high-load microelectrical contacts, arc erosion-resistant ignition electrodes, and neural stimulation and recording wire. In research, it is deployed in applications requiring the hardness and dimensional stability of higher-iridium alloys without complete sacrifice of processability.