51314-3927-Development of Anti-Cathodic Disbonding Performance of an Epoxy Coating

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Product Number: 51314-3927-SG

ISBN: 3927 2014 CP

Author: zhongzhi han

Publication Date: 2014

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Cathodic disbonding is one of the main cause of failure for the epoxy coatings on steel structures under cathodic protection when immersed in seawater. This article has discussed the factors affecting cathodic disbonding of the coatings and developed an epoxy coatings with excellent anti-cathodic disbonding performance and good comprehensive performance when immersed in seawater. The orthogonal test of four factors and four levels was applied to the selection of the type and addition level of the resins. No obvious corrosion could be observed on the coatings after 720h of high temperature seawater resistance and acid/alkalis resistance testing. Additionally the cathodic disbonding test (48h -1.5V (vs. SCE) 65? seawater ) of the coatings shows that the cathodic disbonding equivalent diameter of the coatings (80g bisphenols A epoxy resin 20g bisphenols F epoxy resin 8g novolac epoxy resin and 10g petroleum resin) is minimum distance and 9 mm. The blended curing agent of polyamide and modified phenolic amine was featured by its good overall performance. When the rate of polyamide and modified phenolic amine was 2:1 the anti-cathodic disbonding performance of the coatings was the best. The pigments and fillers of the coatings could improve the mechanical properties adhesion and the corrosion resistance?The P/B ratio was determined at 1:1 based on the test result of relationship between P/B ratio (0.75:1~1.5:1) and comprehensive coating performance?The anti-cathodic disbonding epoxy coatings was prepared under optimum condition according to the above test results. The epoxy coatings has excellent corrosion resistancegood flexibility good wetting and adhesion especially the only 13 mm cathodic disbonding equivalent diameter after the cathodic disbonding test (30d -1.5V (vs. SCE) 65? seawater ).