Corrosion vapor phase inhibitors

Vapor-phase inhibitors are volatile compounds that adsorb onto metal surfaces, and retard or prevent corrosion by a variety of mechanisms (37). Inhibitors such as dicyclohexamine nitrate [3882-06-02] can protect a variety of metals such as steel, aluminum, and tinplate. A number of vapor-phase inhibitors are commercially available as powders or tablets. However, vapor-phase inhibitors attack nonferrous metals to varying degrees, thus the manufacturers recommendations should be checked before appHcation. The system to be protected must be closed to maintain the volatile compound, but objects as large as the interior of an ocean-going tanker have been treated by this technique. 

Vapor phase inhibitors These are used for the temporary protection of new plant in transit or prior to commissioning. Volatile corrosion inhibitors such as cyclohexylamine derivatives are used. The plant must be sealed or contained to prevent rapid loss of the inhibitor. Sachets of these materials are placed in packing cases. Papers impregnated with them are available for wrapping steel items. These inhibitors are used primarily to protect steel. 

Vapor phase inhibitors/volatile corrosion inhibitors (VCI)... 

J.M. Bastidas, E.M. Mora, S. FeHu, The protective action of two vapor-phase inhibitors on the corrosion of mild steel, Werkst. Korros. 41 (1990) 343—347. 

Vapor phase inhibitors (VPIs), also called volatile corrosion inhibitors (VCIs), are compounds that are transported in a closed system to the site of corrosion by volatilization from a source. In boilers, volatile basic compounds such as morpholine or octadecylamine are transported with steam to prevent corrosion in condenser tubes by neutralizing acidic carbon dioxide (Boles et al. 2009). Compounds of this type inhibit corrosion by making the environment alkaline. In closed vapor spaces, such as shipping containers, volatile solids such as the nitrite, carbonate, and benzoate salts of dicyclohexylamine, cyclohexylamine, and hexamethyleneimine are used. 

Industrial application of inhibitors involves acidic, neutral, and alkaline solutions as well as the gas phase. Physical and electrochemical inhibitors can be used for acids, whereas all three types are employed in neutral and alkaline solutions. Gas and vapor phase inhibitors (i.e., substances with high pressure) have gained importance, especially in atmospheric corrosion protection in storage and transportation. 

Uses Corrosion inhibitor in water treatment, vapor phase inhibitor programs Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, Climax Molybdenum http //www. climaxmolybdenum. com, FI u ka http //www.sigma-aldrich.com, Noah http //www.noahtech.com, Quaker City http //WWW. chemical, net Varsal Instruments http //www.varsal.com Trade Name Synonyms ADM [Climax Molybdenum... 

An inhibitor is a chemical substance that, when added in small concentration to an environment, effectively decreases the corrosion rate. There are several classes of inhibitors, conveniently designated as follows (1) passivators, (2) organic inhibitors, including slushing compounds and pickling inhibitors, and (3) vapor-phase inhibitors. 

Detailed data have been presented for dicyclohexylammonium nitrite [31], which is one of the most effective of the vapor-phase inhibitors. This substance is white, crystalline, almost odorless, and relatively nontoxic. It has a vapor pressure of 0.0001 mmHg at 21°C (70°F), which is about one-tenth the vapor pressure of mercury itself. One gram saturates about 550m (20,000ft ) of air, rendering the air relatively noncorrosive to steel. The compound decomposes slowly nevertheless, in properly packaged paper containers at room temperature, it effectively inhibits corrosion of steel over a period of years. However, it should be used with caution in contact with nonferrous metals. In particular, corrosion of zinc, magnesium, and cadmium is accelerated. 

Volatile corrosion inhibitors (VCls), also called vapor phase inhibitors (VPIs), inhibit corrosion by being transported as a vapor from a permeable container to the site susceptible to corrosion. In boilers. 

Inhibitors can also be classified on the basis of their functions. For instance, chromates and nitrates are called passivating inhibitors because of their tendency to passivate the metal surface. Some inhibitors, such as silicates, inhibit both the anodic and cathodic reactions. They also remove undesirable suspended particles from the system, such as iron particles, by precipitation. Certain types of inhibitors make the surrounding environment alkaline to prevent corrosion. Such inhibitors in the gas phase are called vapor phase inhibitors, and they consist of heterocyclic compounds, such as cyclohexylamine. These inhibitors are used within packing crates during transportation by sea. 

Vapor phase inhibitors, like dicyclohexy-lamine, inhibit the corrosion most importantly by... 

Miksic, B. A., Use of Vapor Phase Inhibitors for Corrosion Protection of Metal Products, in Raman, A., and Labine, P. (eds.), Reviews on Corrosion Inhibitor Science and Technology, Houston, Tex., NACE International, 1993, pp. II-16-1-II-16-13. 

Volatilization has already been discussed under vapor phase inhibitors in connection with boilers and closed containers. Another application is the inhibition of gas condensate corrosion. However, the treatment here is essentially the same as used in batch or squeeze treatments. 

Ammonium nitrate finds major applications in explosives and fertilizers, and additional uses in pyrotechnics, freezing mixtures (for obtaining low temperatures), as a slow-burning propellant for missiles (when formulated with other materials, including burning-rate catalysts), as an ingredient in rust inhibitors (especially for vapor-phase corrosion), and as a component of insecticides. 

The inhibitors considered thus far are either liquids or solids dissolved in solvents. Other useful type of inhibitors are vapor-phase corrosion inhibitors. These are used to minimize corrosion in electronics, packaging, processing industries, reinforced concrete,... 

Use Synthesis of dyes, pharmaceuticals, surface-active agents, vapor-phase corrosion inhibitor, antioxidant for chlorophyll, mosquito repellent. 

Inhibitor No. 3. [Oxidinc.] Metalworking coolant arWdve, vapor phase corrosion inhibitor. 

Beilstein Handbook Reference) AI3-26287 1-Amino-2-ethylhexan Armeen LSD BRN 1209249 CCRIS 4646 EINECS 203-233-8 1-Hexanamine, 2-ethyl- P-Ethylhexylamine 2-Ethyl hexylamine 2-Ethylhexanamine 2-Ethylhexylamine Hexylamine, 2-ethyl- UN2276. A chemical intermediate for vapor phase corrosion inhibitors. Akzo Chemie. 

U.S. Patent 5715945, B 65 D 85/84. Vapor phase corrosion inhibitor package utilizing plastic packaging envelopes. C. Chandler, 1998. 

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