"Two coating materials, each with and without the addition of a vapor phase corrosion inhibitor (VCI), were tested by KTA. There was no decrease in tensile adhesion
strength properties for either coating material due to the addition of the VCI agent. Addition of the VCI agent to the MIL-DTL-24441 primer resulted in a measurable reduction in the degree of
coating failure observed at the “X” scribed areas on both the rusted and white metal substrates. The MIL-DTL-24441 primer with VCI agent provided better resistance to corrosion than
Sherwin-Williams zinc phosphate primer with respect to both rust creepage and overall degree of rusting. (Link)
Vapor phase migratory corrosion inhibitor solutions (VCI Agents) dissolved in a variety of solvents at concentrations between 40 to 70 weight percent are made ready for addition to coating manufacturing processes.
VCI Coatings, LLC manufactures a unique 2 part polyamide epoxy primer coating having superior corrosion prevention properties by virtue of the addition of a high performance vapor phase migratory corrosion inhibitor VCI Coating Agent 12. The primer conforms to MIL-DTL-24441in all formulas and types as modified by the addition of the VCI Coating Agent 12 to Part A in an amount that when Parts A and B are combined and applied the resulting dry film contains 2.5 Wt, % of the VCI agent.
Performance properties are measured with and without the VCI agent added to the primer applied on black beauty abraded steel panels in the white metal and 24 hour salt fog exposed corroded conditions. The primer applied at a dry film thickness of 3 mils is exposed for 500 hours in a salt fog chamber in accordance with ASTM 8117. Dry film adhesion before exposure is rated at 5B (no loss) per ASTM 03359 on all samples of coated steel. Corrosion resistance is measured per ASTM 01654 (Evaluation of Painted Specimens Subject to Corrosive Environment) where a rating of 10 is zero degree of creep away from the X scored area and a rating of 1 is 13 to 16 millimeters of creep, and ASTM 0610 for the percentage of surface covered with rust spots where 10 is no rust and 1 is 56 to 75 percent of surface rusted.