Slightly lesser in frequency than elemental causes, particulate matters are one of the major causes of coatings failure in facilities. If surfaces are not properly prepared or cleaned prior to epoxy coatings application, the presence of dust, dirt, grease and other foreign particles hinder the epoxy coatings from totally bonding with the surface to be coated. The lesser adhesion of the applied coatings increases the possibility of premature coatings failure.
In steel surfaces, the presence of nearly-invisible salt deposits often remain despite surface sandblasting, attacking the metal surface underneath the epoxy coatings, causing irreversible corrosion and eventual coatings failure. Surface preparation through hydro blasting can remove these residual particles.
Causes of Coatings Failure
Solvents sometimes help in dissolving foreign particles in epoxy coatings, but the downside to using solvents in epoxy coatings is that they can often result in surface ridges in coated surfaces where there are thick coatings. If the coated surface dried too quickly, trapped solvents underneath will form these ridges and cause the topcoat to fail. The only solution is to use solvent-free epoxy coatings.
Other causes of coatings failure are the inherent brittleness of phenolic epoxy coatings that crack when surfaces move, expand, or contract. When coatings crack, they open the surface to corrosion and moisture damages. To solve brittleness, the epoxy coatings product must have good elongation properties. Porous epoxy coatings, on the other hand, lead to blistering because water or chemicals are freely absorbed by the coatings. Knowledge of non-porous epoxy coatings and their application can help lessen the risk of coatings failure.
