REACTIONS OF POTENTIALLY SUITABLE VCI COMPOUNDS WITH NONFERROUS METALS.
ARMY WEAPONS COMMAND ROCK ISLAND ILL RESEARCH AND ENGINEERING DIV
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Restrictions currently exist in the use of volatile corrosion inhibitors VCI because of the adverse effects on some nonferrous metals and nonmetals. Work was initiated to develop VCIs which would be inert or passive to both nonferrous metals and nonmetals but still have the ability to vaporize to to combat a corrosive environment. Possible VCI compounds were selected and their vapor pressures were measured by the Torsion-Effusion method. Vapor pressure data was obtained for amines of the nitrites, carbonates, benzoates, chromates and caprylate at 21 C. Values ranged from 0.00001 to 0.0048 mm of Hg. Vapor pressure-temperature curves were determined for benzylamine carbonate and dicyclohexylamine caprylate. Reactivity tests were conducted showing the nature and intensity of the attack of the VCI compounds on nonferrous metals. The test consisted of exposing Cu, Cd, Mg, Zn and Al specimens to the VCI compounds for 7 days at 150 F. in the presence of high humidity. Weight loss measurements were used to evaluate the attack on the metals in mils penetration per year mpy. On the basis of the results obtained the following conclusions were made. a Cadmium and magnesium are more severely attacked by the VCI compounds in the presence of water vapor than the other metals tested, b there is not one of the VCI compounds which decreases the corrosion rate of all the metals tested or which has the least corrosive effect and c no correlation was found between the vapor pressures and the reactivity with nonferrous metals. Author
- Fabrication Metallurgy