Effectiveness epoxy coatings

Adhesives and sealers can be an important part of a total corrosion protection system. Structural bonding procedures and adhesives for aluminum, polymer composites, and titanium are well established in the aerospace industry. Structural bonding of steel is gaining increasing prominence in the appliance and automotive industries. The durability of adhesive bonds has been discussed by a number of authors (see, e.g., 85). The effects of aggressive environments on adhesive bonds are of particular concern. Minford ( ) has presented a comparative evaluation of aluminum joints in salt water exposure Smith ( ) has discussed steel-epoxy bond endurance under hydrothermal stress Drain et al. (8 ) and Dodiuk et al. (8 ) have presented results on the effects of water on performance of various adhesive/substrate combinations. In this volume, the durability of adhesive bonds in the presence of water and in corrosive environments is discussed by Matienzo et al., Gosselin, and Holubka et al. The effects of aggressive environments on adhesively bonded steel structures have a number of features in common with their effects on coated steel, but the mechanical requirements placed on adhesive bonds add an additional level of complication. 

T. Nguyen and E. Byrd, FTIR-RA spectral characteristics of epoxy coatings on cold-rolled steel effects of film thickness and angle of Incidence, Appl. Spectrosc. submit for publication, 1985. 

Intermittent rock layers or ledges would restrict the cost effective installation of the lET barrier. In addition, the installation of the lET barrier in caving sands or gravel is difficult and in some cases possible only to a depth that shoring will allow. Epoxy-coated and sealed joint sheet pile may be used to create the barrier in instances where sand and gravel are a problem. AU information is from the vendor and has not been independently verified. 

A simple and effective way of incorporating such a cation-exchange material into the interfacial region would be to apply it to the metal surface as a final pretreatment process. This way the released hydrogen ions would be present in the immediate vicinity of the hydroxide ion generation sites. Therefore, the hydroxide ions could be promptly neutralized and the hydrolysis of the epoxy coating by strong alkali minimized 91>. 

Effect of Pigment Dispersion on Optical Properties and Durability of a TiOi Pigmented Epoxy Coating... 

Figure 10.5 The effect of polysulphide modifications to epoxy coatings [A] epoxy coating modified with polysulphide co-polymer [B] unmodified epoxy coating. Reproduced with permission from Morton International Ltd, Coventry, UK...

Epoxy coating of reinforcing bars is a protective technique developed in the 1970s in North America. Laboratory results confirmed the effectiveness of the epoxy-coated bars, in many cases, in preventing corrosion of reinforcement in carbonated or chloride-contaminated concrete [46]. Recently, however, doubts have arisen about their long-term durability in very aggressive environments, doubts borne out above all by negative experience reported on structures in tropical environments [47-49]. 

K. C. Clear, Effectiveness of epoxy-coated reinforcing steel , Concrete International, 1992, 5, 58—62. 

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