Carbon seal faces are soft, wearing, embeddable seal faces with good emergency running properties. As a rule they are employed against hard, wear-resistant face materials (face material combination). They are usually artificial carbon referred to as hard burnt carbon (hard coal, carbon), carbon graphite (carbon, graphite) or electrographite, depending on their composition. A distinction based on the impregnation is also drawn between resin impregnated carbons and metal-impregnated carbons. Within these groupings there is an additional categorization in blanks for further processing and moulded parts (PTS design). These grades are supplemented by resin-bonded carbon graphite.