Abstract
Superior corrosion resistivity of nickel-chromium coating can be presumed to some extent from the electrochemical investigation previously reported.
A series of corrosion tests, including outdoor exposure at seaside, was carried out to study the performance of copper-nickel-chromium and double nickel-chromium plated steel test pannels.
As a result, the following conclusions were obtained:
(1) In the salt spray and sulfur dioxide test, any superiority of the double nickel-chromium coatings to the copper-nickel-chromium coating was not observed.
(2) In the Korrodkote and CASS test, the performance of the former was excellent, regardless of the thickness. On the other hand, the latter was rapidly deteriorated.
(3) In the outdoor exposure at seaside, the former with total thickness of 30μ was excellent, but the former with total thickness of 20μ was often inferior to the latter with total thickness of 40μ.
(4) As the proportion of semibright nickel in a double nickel coating is increased, its durability in the outdoor exposure increases. Contrary to this, quite reversed phenomenon was observed in the Korrodkote and CASS tests.
