Thin Polyheteroaromatic Interlayers on Commodity Metals for Corrosion Protection

摘要

Polyheteroaromatic (PHA) interlayers of a thickness of a few nanometers and exclusive coatings up to 30 micrometers are applied to steel surfaces by conventional coating procedures. Two special chemical polmers, poly (3-octylthiophene) 1 and poly (N-cyclohexylpyrrole) 2 were studied in detail. They carry large aliphatic substituents to achieve a solubility in organic solvents. Thick layers up to 30 μm yield a corrosion protection factor up to 90% through a barrier mechanism. More interesting are thin interlayers of a few nanometers with a 20 μm topcoating of cathodic paint. Corrosion testing shows a significant improvement over the case of a direct coating of the steel surface through an inhibitor function. A comparison was made to anodically deposited PHA's and to zinc- and iron phosphate interlayers.