Rhodium additional to platinum in tiny amounts yields alloys that are more durable and get rid of weight at high temperatures even more gradually than pure platinum. Such alloys are employed for laboratory furnace crucibles, spark-plug electrodes, and catalysts in really hot chemical environments (together with car catalytic converters). https://rhodiumbullion57788.59bloggers.com/36187505/tuvalu-rhodium-coin-for-dummies