VCIs are originaly developed to protect boilers and piping systems of ships to be mothballed, the volatile corrosion inhibitor(VCI)has been modified over the years to protect electronics, pacaged items,reinforced concrete, coated metaland mateal working fluids. VCIs are powerful tool in combatting atmospheric corrosion of metal and alloys. Because they are volatile at ambient temperature, VCI compounds can reach inaccessible crevices in metallic structures.Protective vapors disseminate within an enclosed space until reaching equilibrium,which is determined by the partial vapor pressure of the VCI compound.The inhibiting process starts when the vapours contact the metal surface and condense to form a thin film of microcrystals. In the presence of even minute quantities of moisture, the crystals dissolve and develop strong ionic activity. Ad sorption of mixed VCI compounds changes the energy state of metallic ions on the surface, diminishing the tendency of metal to ionized and dissolve.