Evaluations have been conducted on: layered coatings, powdered alloy coatings, prealloyed wire coatings and pseudo alloy (from co-jointly sprayed pure wires) coatings. After six months of atmospheric and splash and spray exposure, zinc-aluminum pseudo alloy coatings provide the best overall corrosion performance. Attack of the zinc-15% aluminum prealloyed wire coating along the oxide layers was noted after six months immersion in seawater. The corrosion resistance of thermally sprayed aluminum coatings is due to a passive oxide/hydroxide film which is stable in the region from E//c//o//r//r to approximately minus 550mv (vs SCE). Zinc-aluminum or aluminum-zinc alloy coatings appear to be capable of combining the long-term protection of aluminum and the cathodic protection capabilities of zinc. Low carbon (1018) steel substrates were used for the field exposure tests and 1018 steel and inert polytetrafluoroethylene (PTFE) substrates were used for the electrochemical tests.
|Original language||English (US)|
|State||Published - Dec 1 1985|
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