Carbon rings are widely used as a seal ring in Mechanical seals mainly because of its following UN-matched properties.High wear resistance
It has the advantage of being a comfortable material with good dry running properties, wide temperature range and extensive chemical resistance. It is superior with respect to temperature ,chemical compatibility range and recovery from transient upset ,with the ability to re-establish a carbon transfer film.
Seal carbons are then impregnated to improve the properties. It is very common to impregnate the seals with synthetic resin to convert the porous structure into a low permeable material. Higher duty materials can be impregnated with metal which can provide an increase in the hardness and strength together with improved conductivity. A popular metal impregnated for seal carbons is antimony. It is important for the metal to also have good bearing properties. The temperature limit of the finished carbon component is usually dictated by the manufacturing process and impregnates that may be used. This will be for instance the limit of the resin bonded or impregnated materials and the 'wiping' temperature of a bearing metal. For non-impregnated grades the short-term limit of carbon graphite material is up to 350 Degrees C. and up to 500 Degree C. for graphite's material.
FEATURES OF CARBON SEAL RINGS