Pt10Ir

Pt10Ir refers to an alloy composed of 10% iridium (Ir) and 90% platinum (Pt) by weight. This platinum-iridium alloy is known for its exceptional hardness, high melting point, and excellent resistance to corrosion. The addition of iridium significantly increases the tensile strength and hardness of platinum, making Pt10Ir a more durable material for demanding applications.

Historically, Pt10Ir alloys have been crucial in scientific and industrial endeavors. One of its most prominent historical uses was in the manufacturing of the International Prototype Kilogram (IPK) and the International Prototype Meter (IPM). The IPK, a standard for mass, was made of Pt10Ir for its stability and resistance to deformation over time. Similarly, the original International Prototype Meter bar was also composed of this alloy.

Beyond metrology, Pt10Ir finds application in various specialized fields. Its high melting point and corrosion resistance make it suitable for use in crucibles for high-temperature melting of materials, electrodes in high-energy applications, and spark plug electrodes in certain high-performance engines. The alloy's electrical conductivity, while lower than pure platinum, remains sufficient for many electrical contact applications where durability and resistance to oxidation are paramount. Due to its cost and specialized nature, Pt10Ir is typically used where its unique properties justify the expense.