Corrosion preventing compounds

As a result of the numerous corrosion problems of the KC-135, the Air Force in the United States expended considerable effort to develop methods to contfol corrosion of the KC-135 ranging from characterizing the type and extent of corrosion to developing new nondestructive techniques, to developing methods to slow down corrosion with corrosion preventative compounds (CPCs), and to developing predictive models. 

Corrosion prevention compounds (CPCs) are fluids that can both prevent new corrosion sites from forming (Fig. 14.6) and, more importantly, suppress any corrosion that has initiated. CPCs are... 

Salagaras M, BusheU PG, Trathen PN, Hinton BRW. The Use of Corrosion Prevention Compounds Jbr Arresting the Growth of Corrosion in Aluminium Alloys. Fifth Joint NASA/FAA/DoD Conference on Aging Aircraft, Orlando, Fla. September 10-13,2001. 

Close tolerance parts not exposed to outdoor atmospheres should be protected by corrosion-preventive compounds. 

Replacing one carbon atom of naphthalene with an a2omethene linkage creates the isomeric heterocycles 1- and 2-a2anaphthalene. Better known by their trivial names quinoline [91-22-5] (1) and isoquinoline [119-65-3] (2), these compounds have been the subject of extensive investigation since their extraction from coal tar in the nineteenth century. The variety of studies cover fields as diverse as molecular orbital theory and corrosion prevention. There is also a vast patent Hterature. The best assurance of continuing interest is the frequency with which quinoline and isoquinoline stmctures occur in alkaloids (qv) and pharmaceuticals (qv), for example, quinine [130-95-0] and morphine [57-27-2] (see Alkaloids). 

Hence, the hot-dip compounds, or greases smeared cold, are better for assemblies with non-metallic parts masked if necessary. Solvent-containing protectives therefore find greater application in the protection of simple parts or components. The available means of application, the nature of any additional packaging and the economics and scale of the protective treatment are further factors that influence the choice of type of temporary corrosion preventive. 

MIL-A-8576 MIL-A-9117 MIL-A-12850 MIL-C-14064 MIL-C-15705 MIL-C-18255 MIL-C-18969 MIL-C-23092 MIL-C-27315 MIL-C-27725 MIL-C-5539 MIL-C-7438 Adhesive, Acrylic Monomer Base Synthetic Elastomeric Sealant Natural Liquid Rubber Cement Grinding Disk Cement Caulking Compound Caulking Compound with Synthetic Rubber Base Caulking Compound—Watertight Exterior Hull Seams of Vessels Cement, Natural Rubber Coating Systems, Elastomeric Coating, Corrosion, Preventative, Air Fuel Tanks Natural Rubber Cement Core Material, Aluminum, for Sandwich Construction... 

Corrosion Preventatives Metalworking Compounds Hydraulic Fluids... 

Carbon dioxide (ASTM D-1137, ASTM D-1945, ASTM D-4984) in excess of 3% is normally removed for reasons of corrosion prevention (ASTM D-1838). Hydrogen sulfide (ASTM D-2420, ASTM D-2385, ASTM D-2725, ASTM D-4084, ASTM D-4810, IP 103, IP 272) is also removed, and the odor of the gases must not be objectionable (ASTM D-6273) so mercaptan content (ASTM D-1988, ASTM D-2385, IP 272) is important. A simple lead acetate test (ASTM D-2420, ASTM D-4084) is available for detecting the presence of hydrogen sulfide and is an additional safeguard that hydrogen sulfide not be present (ASTM D-1835). Methyl mercaptan, if present, produces a transitory yellow stain on the lead acetate paper that fades completely in less than 5 min. Other sulfur compounds (ASTM D-5504, ASTM D-6228) present in liquefied petroleum gas do not interfere. 

Concrete hardening compounds Core oil and binders Core wash Core wax Correction fluid Corrosion preventive lubricant, synthetic base for jet engines Deicing fluid Desalter kits, sea water Dextrime sizes Drilling mud Dyes, household Essential oils Ethylene glycol antifreeze preparations Eucalyptus oil Exothermics for metal industries... 

ANTIFOULANTS - Are materials which prevent fouling from depositing on heat transfer equipment. Materials that prevent deposits forming include anti- oxidants, metal coordinators, and corrosion inhibitors. Compounds that prevent deposition are surfactants. They act as detergents or dispersants. 

A. Minhaj, PA. Saini, M.A. Quraishi, I.H. Earooqi (1999). A study of natural compounds as corrosion inhibitors for industrial cooling systems. Corrosion Prevention and Control 46(2), pp. 32-38. 

A final approach to corrosion prevention is the use of an inhibitor, defined as a substance used in small concentrations that decreases the rate of corrosion. Most inhibitors are organic compounds that form adsorbed layers on the metal surface. This provides a system similar to the protective coatings discussed earlier. Other inhibitors affect gaseous reduction reactions associated with the cathode (Table 20.5). 

Natural gas is mainly (from 75% to 90%) composed of methane. It also contains undesired components such as acid gaseous impurities like carbon dioxide or hydrogen sulfide that should be removed to prevent pipeline corrosion condensable compounds (higher C2+ hydrocarbons and water) that must be removed in order to prevent condensation troubles, hydrate formation, or corrosion when flowing natural gas in pipelines and inert gases, such as nitrogen, which lower the calorific value of natural gas. ... 

Rarerearth metal (R) compounds have been used in the protection of metals from oxidation at hi temperatures for many years. This subject is the topic for another review by Dr. Neil Ryan in this volume (see ch. 141). In the last 10 years, soluble R salts have also been eonsidered for application in corrosion prevention and control at low temperatures i.e. below 100°C. It is the purpose of this chapter to review published research, which demonstrates how these salts may be used to control and prevent corrosion... 

It has been shown that R metals and compounds are capable of being used in many of these roles. Moreover, it is an area of application for R metals that is relatively new, and consequently, the reasons why they improve corrosion resistance are not completely understood. Clearly, in most of the areas described during the course of this chapter, considerably more research is required. However, there is one common factor which seems to be central to the whole topic of corrosion prevention and control with R metals and compounds, namely the effective formation/participation of a R oxide or hydroxide film. 

In 1964 Prof Ceilings was appointed professor of Inor nic Chemistry and Materials Science at the University of Twente. His main research interests were coordination chemistry and spectroscopy of transition metal compounds, corrosion and corrosion prevention, and catalysis. In 1991 he received the Cavallaro Medal of the European Federation Corrosion for his contributions to corrosion research. In 1992 he retired from his post at the University, but has remained active as supervisor of graduate students in the field of high temperature corrosion. 

Vapor-phase inhibitors (VPIs), also called volatile corrosion inhibitors (VCIs), are compounds which 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. Corrosion inhibitor compounds vaporize from the paper or film. They are attracted to the charged surface of the metal by virtue of their polar orientation. 

The second detergent function is to prevent formation of varnishes that come from polymerization of deposits on hot surfaces of the cylinder and the piston. Finally, by adsorption on metallic surfaces, these compounds have anti-corrosion effects. 

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