Anti-corrosive finishes

Whitfield, M. G., Rolling of Hot Dipped Aluminized Steels to Make Them More Durable , Anti-Corrosive Materials and Processes, 2, 31, Oct. (1963) and US Pat. 2 170 361 Anon., Largest Aluminium Line in UK , Product Finishing, 21 No. 7, 61-65, July (1968) Anon., Welded Aluminized Steel Sheet , Anti-Corrosive Materials and Processes, No. 2, 4-7, Oct. (1963)... 

Good quality steel is used and electrozinc is preferred for washing machines. Steel is pretreated with iron phosphate for economy electrozinc with a fine crystal zinc phosphate. No primer is normally used 25-40/im of finish is applied direct to metal. The required properties are best obtained with a thermosetting acrylic or polyester/melamine-formaldehyde finish. Self-reactive acrylics are usually preferred these resins contain about 15 Vo 7V-butoxymethyl acrylamide (CH2=CH —CO —NH —CHj—O —C4H,) monomer and cure in a manner similar to butylated melamine-formaldehyde resins. Resistance or anti-corrosive properties may be upgraded by the inclusion of small amounts of epoxy resin. Application is usually by electrostatic spray application from disc or bell. Shapes are complex enough to require convected hot-air curing. Schedules of 20 min at 150-175°C are... 

Salt spray test n. A test applied to metal finishes to determine their anti-corrosive properties, involving the spraying of common salt (sodium chloride) solution on the surface of a coated steel panel. 

It is seen in Table IV that both pilot plant samples (finished samples plus additives) passed the copper corrosion test, as did most of the additive-free refinery samples. However, all fourteen of the additive-containing refinery samples failed. These fourteen samples were all finished sairples and contained AO-30. Since the six DFM samples which failed the test did not contain FSII, it is assumed that this additive did not play a part. Since the two pilot plant samples (containing AO-29) passed the test, and the fourteen refinery samples (containing AO-30) failed, questions are raised concerning the anti-oxidant additives which were used. These results need to be related to the sequence of operations in the refinery process and to the nature of the additives which were used. It seems probable that either there was a problem with the acid treatment process by which a corrosive species was produced which ended up in the finished samples, or that the additives used may have been contaminated. Both aspects may be involved. 

Uses Emulsifier for industrial detergents, adhesives, pesticides dispersant detergent intermediate for quat. ammonium compds. strongly absorbed on textiles, paper, many metal surfs. for asphalt, cleaners, demulsifiers, metalworking, paints corrosion inhibitor for lubricant additives, oil field chems. flotation collector for sulfide ores petrol, antiicing additive pigment grinding inks, wax emulsions softener, anti-stat for syn. fabrics, textile finishes antistat in cosmetics Trade Names Crodazoline S Imidazoline S OH... 

The noble metals, i.e. gold, platinum, palladium, and rhodium, and the corrosion-resistant metals, i.e. chromium, nickel, tin, tin-lead solder, and titanium, require no finish other than cleaning. Soldered joints should be protected with a moisture-proofing compound or coating. Corrosion-resistant (or treated to resist corrosion) minor devices (fasteners, etc.) should be used. Fasteners should be treated with zinc chromate, zinc chromate paste, or graphite-free dry-film anti-seize compound. 

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