Platinum-iridium alloy is a binary alloy containing iridium, which is a continuous solid solution at high temperature. Iridium is volatile and oxidized and can significantly improve the corrosion resistance of platinum. Ptlrl0, Ptlr17.5, Ptlr25, Ptlr30 and other alloys have high hardness, high melting point, high corrosion resistance and low contact resistance. The chemical corrosion rate was 58% of pure platinum, and the oxidation weight loss was 2.8mg/g. It is a classic electrical contact material used for ignition contacts of aero-engines, high sensitivity relays and electrical contacts of micromotors. Potentiometers and conducting rings and brushes for precision sensors such as aircraft, missiles and gyroscopes.
Platinum-iridium alloys have high melting point, high density, high hardness, high strength and high elasticity, which are enhanced with increasing iridium concentration. (2) Alloys with more than 10% iridium content have aging hardening effect and increase with iridium concentration, but the precipitation rate is low. (3) The resistivity of platinum-iridium alloy increases with the increase of Ir concentration, but the resistance temperature coefficient decreases. The contact resistance of platinum-iridium alloy is low, but it is easy to be polluted by organic atmosphere. Platinum-iridium alloy has positive thermoelectric potential to platinum and increases with the increase of iridium concentration. (4) The addition of iridium to platinum significantly improves the chemical corrosion resistance of platinum, and alloys containing more than 30% iridium are actually not corrode by boiling aqua regia. (5) With the increase of iridium concentration and heating temperature, the loss of platinum iridium alloy volatilization increases. (6) Platinum-Iridium alloys have high deformation resistance and work hardening rate, and the work performance becomes worse with the increase of iridium content; Intra - crystal segregation and dendritic crystal development of the alloy must be processed by high temperature before cold processing.
(1) Platinum-iridium alloys have high melting point, high density, high hardness, high strength and high elasticity, which are enhanced with the increase of iridium concentration.
(2) Alloys with more than 10% iridium content have aging hardening effect and increase with iridium concentration, but the precipitation rate is low.
(3) The resistivity of platinum-iridium alloy increases with the increase of Ir concentration, but the resistance temperature coefficient decreases. The contact resistance of platinum-iridium alloy is low, but it is easy to be polluted by organic atmosphere. Platinum-iridium alloy has positive thermoelectric potential to platinum and increases with the increase of iridium concentration.
