An earth-boring bit has a mechanical face seal assembly with PCD faces. The bit has a bearing shaft with a cone rotatably mounted on the bearing shaft. The seal locates between the bearing shaft and the cone for sealing lubricant therein. The seal includes at least one rigid seal ring having a carbide...http://www.google.de/patents/US6684966?utm_source=gb-gplus-sharePatent US6684966 - PCD face seal for earth-boring bit
