Triboelectromagnetic phenomena of an emission of negatively and positively charged particles were measured during sliding of a diamond on a carbon film with various hydrogen contents under perfluoropolyether (PFPE) fluid lubrication. This tribosystem simulates the material combination of a head slider coated with a diamond-like carbon film and the magnetic recording disk coated with hydrogenated carbon films under PP;PE lubrication. The emission intensities were low on the carbon film with low hydrogen content. There was a transition from low to high emission intensity with increasing hydrogen content. The minimum friction coefficient occurred in the regime in which triboemission was high. Tribocharging increased with the increase of the hydrogen content.