The article presents the results of studies on the destruction of the surface layer of epoxy coatings subjected to ultraviolet radiation or 20% aqueous solutions of: sodium chloride, sulfuric acid, and potassium hydroxide. X-ray and infrared spectroscopic studies documented significant oxidation of the surface layer of the aged coatings, indicating their chemical destruction.Physical destruction of the coatings manifested as a decrease in hardness and an increase in surface roughness. The greatest changes in surface roughness were observed for aging under the influence of a 20% aqueous solution of potassium hydroxide, for which the Ra parameter increased fortyfold after 1320 hours of aging. The aged coatings cracked, and in the case of exposure to a 20% aqueous solution of sulfuric acid, blistering of the coatings also occurred.
EXAMINATION OF SURFACE LAYER OF EPOXY COATINGS AGED WITH AGGRESSIVE MEDIA
The paper presents destruction examination results of surface layer of epoxy coatings subjected to action of ultraviolet radiation or 20% water solutions of: sodium chloride, sulphuric acid, and potassium hydroxide. X-ray analyses as well as IR spectroscopic investigations attested the substantial oxidation of aged coatings surface layer what is evidence of its chemical destruction. However physical destruction of coatings revealed itself in the form of hardness decrease and increase of coating surface roughness.
The biggest changes of roughness were stated in the case of ageing under the influence of 20% water solution of potassium hydroxide, after 1230 h of which the Ra parameter increased 40 times. The aged coatings cracked and in the case of 20% water solution of sulphuric acid action the blistering also occurred.
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Source: Logistyka Magazine