is the additive for
protecting lubricated metal surfaces against chemical attack by water or
other contaminants. There are several types of
corrosioninhibitors. Polar
compounds wet the metal surface preferentially, protecting it with a
film of oil. Other compounds may absorb water by incorporating it in a
water-in-oil emulsion so that only the oil
touches the metal surface. Another type of corrosion inhibitor combines
chemically with the metal to present a non-reactive surface.