Comparative Tribological study of Materials in Hydrogen ICE Seat-Valve Systems Using Pin-on-Disc Testing

The durability of the seat-valve interface is critical for the reliable operation of hydrogen-based internal combustion engines (H2ICEs), where harsh operating conditions and fuel characteristics impose stringent demands on material performance. This study presents a comparative tribological evaluation of three different seat materials—comprising two Cobalt and molybdenum-type and a Copper and Berillyum-type alloys—paired with a Stellite F valve material. Using pin-on-disc testing, the investigation simulates the sliding and contact conditions typical of the seat-valve interface in hydrogen ICE applications. The contact conditions have been evaluated by Finite Element Method analyses. Contact pressure and sliding distance have been estimated and used as reference for the experimental tests on the tribometer. A Stellite F pin has been produced for the upper sample, and the seat component has been directly used as the counterface. Key performance indicators, such as wear rate and friction coefficient, were measured under controlled conditions (Fig.1) to assess the tribological performances of the seat materials. The results reveal significant differences in wear behavior among the tested seat materials, with one Cobalt and molybdenum-type alloy demonstrating notably enhanced wear resistance and lower friction, thereby suggesting its potential for extended service life in valves of H2ICE.