Overview of tribology researches for high-pressure hydrogen systems

Recent studies in Kyushu University on tribology for hydrogen energy systems are briefly overviewed. Friction and wear of various materials for valves, dynamic and static seals, piston rings, and bearings are studied in purity controlled test environments and at high pressure. Their tribological behavior depends on gas environment, and more or less on trace impurities in hydrogen. Chemical and tribochemical reactions play an important role in the processes at contacting surfaces. Recent progresses in hydrogen related technologies in Japan are also briefly introduced.