Extreme Pressure Additives or EP Additives

Posted on 24 April 2019

Extreme Pressure Additives (ep additives) are added to the oil in the form of Sulfur or Phosphorous in order to prevent fusing due to high pressures or loads of the friction partners.

Some Gear oils such as our Fuchs Lubricants Mild EP 90 Gear oil only contain small amounts of ep additives so as not to damage certain types of metals used in older gearboxes and diffs.

In this case, ep additives in lubricants are indispensable. Under high pressures or loads, high temperatures are created in the lubricant. This causes Sulfur (sulfur carriers) or a Phosphorous derivative (compounds containing phosphorous) to be released from the ep additive.

Under these conditions, the released substance immediately reacts with the metal surface to metal sulfides or phosphates. The connections form on the metal surface layers that are sheared off under high pressure, with which a fusing of the metal surfaces is prevented.

To view our range of greases containing ep additives click here