Note: Please consider that the PGM ( Pt Pd Rh) content might change from One catalytic to another ( having similar serial #) due to different condition such as mileage weather condition etc.
PtIr & PtRh wires are common in use as thermocouples and resistance thermometers for measuring high temperature up to 1800°c, those temperatures and resistance temperatures thermometers are used in: furnaces, gas turbines, industrial sensors (for airplanes gauges controllers) etc. Rh & Ir content in those wires is from 5%-20% , It is not possible To know the difference without assay.
A.G. Metals
Ami Gur