On the tribological behaviour of mechanical seal face materials in dry line contact: Part I. Mechanical carbon

Mechanical face seal performance is critically dependant on the tribology of the seal face materials. In this research the tribology of the premier seal face materials under dry running contact has been examined. It is shown that the PV (pressure×velocity) capability, of these premier face materials, is dependant on the development of a carbon graphite contact film. Experimentation has shown that these contact films breakdown via a seizure mechanism. The breakdown of the contact film is shown to result in a transition from a very low wear rate regime to a severe wear rate regime. Analysis of the results and the performance profiles produced has allowed the mechanisms of contact film formation and the functionality of the film in solid contact to be identified. A contact model is proposed that describes the low friction characteristic of mechanical carbon by combining the theories of Lancaster and Savage. The model is finally related to the mechanical seal face design.