HYDROGEN PERMEATION MEASUREMENTS ON SOME ELECTRODEPOSITED PROTECTIVE COATINGS FOR HIGH STRENGTH STEELS.
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
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The Report describes the apparatus used and measurements made to determine whether certain standard and special electrodeposited coatings were permeable to hydrogen. Cadmium plating to specification DTD904 showed no measurable permeability at either 30 or 200C. Coatings produced by the Cleveland cadmium plating process were also found to be impermeable at both temperatures, apparently due to a dense layer formed during the early stages of plating. A zinc-nickel alloy electrocoating containing approximately 18 nickel showed no measurable permeability at 30C, but a small permeability was obtained at 200C and this might prove sufficient to allow hydrogen contents to be reduced below embrittling levels. Author
- Metallurgy and Metallography
- Fabrication Metallurgy