Study on Epoxy Coating which Could Be Applied on High Temperature (70°C) Steel Surface

When common epoxy coatings were applied directly on high temperature (usually about 70°C) steel surface, some defects would occur in coating film, such as bubbles, pinholes, loosen and poor quality flow leveling property, etc. These defects lead to reduction in coating’s adhesion, physical properties and anti-penetrability, shorten service life of coatings greatly, making coating losing their protection function. Main reasons for those defects were analyzed briefly in this paper. In high temperature environment, solvents or other volatile organic compounds (VOC) in coatings will volatilize faster than in normal temperature environment, coating may undergo poor quality flow leveling properties, which couldn’t be fixed by itself. Research and development of a new type epoxy coating were introduced in this paper. Several methods were proposed, including selecting suitable resins, adding high boiling point solvent into coating, using leveling agent and other additives. After these modifications, coating’s construction adaptability was improved and could be applied directly on high temperature steel surface. The scanning electron microscopy (SEM) results show that the coating film prepared in high temperature condition have equivalent fine structure with film prepared in normal condition. The physical properties, anti-penetrability and anti-corrosion were also discussed in this paper