Inhibited Coatings

Provide effective means of corrosion protection of components consistent with operational circumstances. This may involve cathodic protection, inhibition, coatings or combinations of these. 

There is a large potential for conducting polymers as corrosion-inhibiting coatings. For instance, the corrosion protection ability of polyaniline is pH-dependent. At lower pH polyaniline-coated steel corrodes about 100 times more slowly than noncoated steel. By comparison, at a pH of about 7 the corrosion protection time is only twice for polyaniline-coated steel. Another area of application involves creation of solid state rechargeable batteries and electrochromic cells. Polyheterocycles have been cycled thousands of times with retention of over 50% of the electrochromic activity for some materials after 10,000 cycles. IR polarizers based on polyaniline have been shown to be as good as metal wire polarizers. 

ISO 1249 - Zinc chromate pigments - Basic zinc potassium chromate pigments and zinc tetrahydroxychromate pigments - specifies the requirements, and corresponding test methods for zinc chromate pigments suitable for use in paints and/or corrosion-inhibiting coatings [5.59]. 

In the case where the exchange current densities of the redox reactions are reduced by the presence of an inhibitive coating... 

Abousalham A, Hobman TC, Dewald J, Garbutt M, Brindley DN. Cell-permeable ceramides preferentially inhibit coated vesicle formation and exocytosis in Chinese hamster ovary compared with Madin- Darby canine kidney cells by preventing the membrane association of ADP- ribosylation factor. Biochem J 361(2002) 653-661. 

An original and simple method of express estimate of the protective ability of inhibited coatings is described in [83]. The cyclic strength of steel wire samples coated by inhibited polyethylene is estimated upon exposition for two to 12 days in a hostile medium (0.2 n aqua solution of sulfuric acid). The index of cyclic strength is taken as the number of bends in opposite directions through 90 degrees preceding failure of the sample. 

Unpeelable inhibited coatings are used largely as primers preceding the paintwork on cars and equipment. 

A scheme of appl3dng an inhibited coating in a polymer melt onto the film base by extrusion lamination [34] is illustrated in Fig. 2.13. A similar procedure is employed at Cortec and Northern Instruments Co. for paper production with a laminated layer of inhibited PE. 

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