Extreme Pressure

Under extreme pressure and severe sliding speeds among two surfaces the oil film is likely to be squeezed out and a thick film of oils is hard to maintain. The squeezing out of the oil from among the contact surfaces results in high instantaneous pressure and increase in temperature. The additives have certain minerals that are absorbed on the metal surface or react chemically with metal generating a surface layer of low shear strength on the metal surface, thus preventing the tearing up of the metal. Another property of high pressure additives is that they react at high temperature on metal surfaces, composing surface alloys so as to prevent the welding together of the rubbing parts under severe operating conditions.