Extreme Pressure Lubrications

While the sliding surfaces are under extremely high pressure and moving with high speed, a high local temperature is reached and under such conditions, liquid lubricants fail to stick and may decompose and even vaporise. In order to meet these extreme-pressure conditions, special additives are added up to mineral oils. These are known as “extreme-pressure additives”. These additives form more durable films on metal surfaces, which are capable of withstanding very high loads and high temperatures. Significant additives are organic compounds having active radicals or groups such like sulphur, chlorine or phosphorus. These compounds react with metallic surfaces at prevailing high temperatures, to form metallic chlorides, sulphide of phosphides. These metallic compounds possess high melting points & serves as good lubricant under extreme-pressure and extreme-temperature conditions. If by chance, the low shear strength films are broken by the rubbing action of moving parts they are immediately replenished.