1 - Scope
This document explains the results of salt fog test performed on whips protected by Nickel and Ni-Cr plating.
These treatments have been identified as possible alternatives and improvement of present standard Chromium
plating, which in some cases showed marks of superficial rust when exposed to normal environment in Thailand.
2 – Preliminary considerations
The test was made to analyze the performance of protective layer when there is the combination of high stress
and very aggressive environment and, in particular, to check the behavior of the whips.
Test conditions are described on standard EN ISO9227, test “Neutral Salt Spray (NSS)” and tab.1.
Test time was minimum 72hours, usually consideredsufficient for normal environmental conditions.
For further investigation the test was continued until 216hours, which according to Coelme experience represents
a long term exposition in a really aggressive environment.
7 - Conclusions
The performance of both protection layers appears acceptable.
Sample 1 (Nickel and Chromium, electrolytic method) shows no red rust marks even after 216h in salt fog.
Sample 2 (Nickel coating, chemical application) shows thin and superficial red rust marks after 216h, located
upon the protective layer surface but not affecting the base metal of the whip.
From the above results, it is possible tostate that both protectivelayers result to be satisfactory for the application
in aggressive environments and that specimens with layer of Nickel and Chromium (electrolytic method) is the
best.
The treatment “Nickel and Chromium, electrolytic method”is therefore chosen for the whips supplied to EGAT
1 - Scope This document explains the results of salt fog test performed on whips protected by Nickel and Ni-Cr plating. These treatments have been identified as possible alternatives and improvement of present standard Chromium plating, which in some cases showed marks of superficial rust when exposed to normal environment in Thailand.2 – Preliminary considerations The test was made to analyze the performance of protective layer when there is the combination of high stress and very aggressive environment and, in particular, to check the behavior of the whips. Test conditions are described on standard EN ISO9227, test “Neutral Salt Spray (NSS)” and tab.1. Test time was minimum 72hours, usually consideredsufficient for normal environmental conditions. For further investigation the test was continued until 216hours, which according to Coelme experience represents a long term exposition in a really aggressive environment.7 - Conclusions The performance of both protection layers appears acceptable. Sample 1 (Nickel and Chromium, electrolytic method) shows no red rust marks even after 216h in salt fog. Sample 2 (Nickel coating, chemical application) shows thin and superficial red rust marks after 216h, located upon the protective layer surface but not affecting the base metal of the whip. From the above results, it is possible tostate that both protectivelayers result to be satisfactory for the application in aggressive environments and that specimens with layer of Nickel and Chromium (electrolytic method) is the
best.
The treatment “Nickel and Chromium, electrolytic method”is therefore chosen for the whips supplied to EGAT
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