PlatinIridium

PlatinIridium, often abbreviated Pt–Ir, is a platinum group metal alloy composed primarily of platinum with a significant proportion of iridium. In common compositions, iridium is present in the range of a few to around twenty percent by weight, with the remainder being platinum. The alloy forms a solid solution that blends the desirable characteristics of both elements, notably enhanced hardness and creep resistance while retaining the high melting point and chemical inertness characteristic of platinum.

Properties of Pt–Ir alloys include very high melting points, excellent oxidation resistance at elevated temperatures, and good mechanical strength for a platinum-based material. The addition of iridium increases hardness and wear resistance compared with pure platinum, and the alloy typically maintains the bright, white appearance associated with platinum-group metals. These attributes make Pt–Ir alloys suitable for demanding high-temperature applications.

Production of Pt–Ir involves melting platinum and iridium together under controlled conditions, often in a vacuum or inert atmosphere, followed by casting or wrought working to form bars, wires, crucibles, or components. The microstructure is generally a single-phase solid solution for many compositions, though processing can influence grain size and toughness.

Common applications include high-temperature crucibles and labware, components in chemical processing equipment, electrical contacts and spark-gap electrodes, and specialized jewelry or watch parts where durability and sheen are desired. The alloy’s combination of extreme temperature stability and resistance to corrosion makes it preferable in environments where pure Pt would be too soft or wear-prone, although its cost and workability considerations limit widespread use.