Iridium

You will find a nearly420 year long low level of interest in the refractory platinum group metals for uses such as rocket nozzles and reentry heat shields.

There was some interest in Rhenium infiltrated carbon/carbon composites as a hypervelocity impact resistant material for nuclear weapons heat shields that could fly through a nuclear debris cloud.

The subject is OLD. After all, the basic properties of all of the platinum group have long been known, and there have always been curious people who think of high temperature uses of materials.

If something has been found wanting a long time ago, not paying attention to hope reborn today for the same old thing isn't "ignoring" the issue.

Research, involves sometimes finding out old stuff, and old reasons for certain actions and attitudes.

Iridium has found a small niche in high performance spark plug manufacture where people seem to be willing to pay for the miniscule performance gains over platinum.

Ir is not so rare, nor expensive. Output is adjusted to demand.

See:

J.J.ù