Cadmium Substitution - garteur
Cadmium Substitution - garteur
Cadmium Substitution - garteur
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GARTEUR LIMITED<br />
8 Conclusions<br />
The main conclusions from the experimental investigation were:<br />
1. None of the coatings evaluated gave an overall performance equivalent to cadmium<br />
plating.<br />
2. Outdoor exposure tests show that ED zinc-cobalt -iron appears very similar to<br />
cadmium in protecting the scribed area in both marine and relatively rural<br />
environments. All other coatings were less effective whilst SermeTel was the least<br />
efficient.<br />
3. For a maximum resistance to corrosion attack a passivation treatment with chromium<br />
VI containing solution is the most promising.<br />
4. Galvanic compatibility with coated fasteners into aluminium alloy blocks indicate that<br />
the Delta-tone coating is the most promising.<br />
5. Resistance measurements indicate that good electrical conductivity with both Hi-Lock<br />
and coated countersink screws can be obtained.<br />
6. With the exception of the Delta-tone coating the coefficients of friction were found to<br />
be significantly higher than cadmium plating.<br />
7. The ED zinc-nickel coating caused the largest reduction in fatigue strength (25%).<br />
ED zinc-cobalt-iron gave no larger reduction than cadmium plating (~10%).<br />
8. Brush plating with zinc-cobalt and zinc-nickel electrolytes could be used for repair<br />
(protection) of a range of Garteur coatings.<br />
GARTEUR SM/AG17 TP128 Page 19
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