One aspect in the improvement of sealing for rotary
engines is the material selection of the seal. The
material must be able to resist the environmental
conditions while performing its main task as a seal. The
main requirements for environmental conditioning are
chemical resistance, resistance to wide temperature
variations, and resistance to corrosion. The main
functions of the seal are high resistance to wear, low
compression set, good elasticity and low friction.
Efforts that concentrate on new material compositions
are a large area of research and development. A
composite hydrogen storage alloy material for rotary
engine parts was proposed [91]. A combination thermal
barrier and wear coating that protects the areas in
contact with moving rotational parts was proposed [92