Mechanical seal rings
The Metcar Grade M-444 is an antimony impregnated carbon-graphite primary seal ring designed for sealing refrigerants and low viscosity liquids. Low viscosity liquids are difficult for mechanical seals because the hydrodynamic film that they create between the two rubbing seal faces is extremely thin. The M-444 is able to counteract this with a self-polishing feature as well as the high dimensional stability of both solid silicon carbide and antimony impregnated carbon-graphite that enables these two materials to run in the required close proximity.
Metallized Carbon Corporation