Aluminum-polyester corrosion

Corrosion. Aqueous solutions of citric acid are mildly corrosive toward carbon steels. At elevated temperatures, 304 stainless steel is corroded by citric acid, but 316 stainless steel is resistant to corrosion. Many aluminum, copper, and nickel alloys are mildly corroded by citric acid. In general, glass and plastics such as fiber glass reinforced polyester, polyethylene, polypropylene, poly(vinyl chloride), and cross-linked poly(vinyl chloride) are not corroded by citric acid. 

Thus, in alkyd, polyester, and epoxy coatings applied to CRS, phosphatized steel, and aluminum, the use of ZAs APG (aminofunctional) and CPG (carboxy-functional) has allowed for the virtual elimination of blister formation and corrosion after 300 h of salt fog exposure. The use of multifunctional ZAs in a Kraton base adhesive has allowed for a 52% increase in T-peel strength on EPDM rubber when compared with the same adhesive containing aminofunctional silane. Incorporation of mercaptofunctional ZA into crosslinkable elastomers has... 

Uses Adhesion promoter for baked alkyds, polyesters, acrylics, and lacquers onto metal substrates corrosion-inhibiting pretreatment or base coating for galvanized steel and aluminum suitable for food-contact coatings... 

Uses Reducing agent in redox-catalyzed polymerization color stabilizer, modifier, catalyst for polyamides antioxidant intermediate for forming metallic salts used as stabilizers accelerator for org. peroxide catalysts improver of polysiloxane resins free radical promoter in emulsion polymerization promoter in polyester resin curing mfg. of self-extinguishing fibers (reacts with polyester resin and polyolefin) color/odor inhibitor, catalyst for some thermoplastics discoloration inhibitor in PE corrosion inhibitor on thin aluminum surfs. lubricity improver in polyphenyl thioether-based lubricants Manuf./Distrib. Akzo Nobel http //www.akzonobel.com, Ferro http //WWW. ferro. com... 

The leading powder is epoxy resin, applied 1 to 50 mils thick this is used for corrosion resistance in auto underbodies, steel rebars for concrete, petroleum industry, appliances, and citrus food cans. Epoxy-polyester powders are more resistant to yellowing and are used 1 to 20 nuls thick for aluminum wheels and architectnral trim. Polyester-polyurethane powders are smooth, flexible, and weather resistant 1 to 3 mil films are used for auto trim, steel wheels, fighting fixtures, patio furniture, and appliances. 

LCP rivets offer an attractive alternative to metal for fasteners without the high cost and high density of titanium or the corrosion problems associated with aluminum. Because Kevlar and liquid crystalline polyesters are strong, nonabrasive, dimensionally stable, and thermally stable, they also have been used to reinforce brake linings [6]. 

The internal floating roof in a covered tank may be a steel pontoon roof, a steel pan roof, an aluminum floating cover with pontoons or floats, or a fiberglass polyester skin panel deck. Aluminum and polyester roofs have a greater fall through potential than steel roofs. In addition, mechanical damage, corrosion, or other defects may not be readily apparent. 

It has been shown that some latent hardeners of the epoxy resins may corrode the aluminum wires or bonding pads. This corrosivity has been demonstrated for the complex of boron trifluoride and monoethyl-amine. In the specification NSA 77-25A, small dots of adhesive are applied to the aluminized side of a Mylar polyester film (www.dupont.com) and are allowed to stand in flie room ambient without cure. After 48 h, the dots are removed from the film by washing with acetone and the requirement is that there are no changes in the light transmission of the film. 

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