Assessment of the Mechanism of Adhesive Destruction Coatings

Abstract

Information on deformation of coatings at different loading levels during peeling is given. It is shown that the deformations of the organosilicon coating appear already at the initial stages of loading, and the obtained data correlate with the data on acoustic emission. For a polyvinyl acetate coating at low loading levels, equal to 0.3-0.4 R, the release of acoustic signal energy is not observed. The absence of signals with a large amplitude at loading levels up to 0.7-0.8 R indicates the development of plastic deformations in the contact zone of the coating with the substrate. It was found that early localization of bond breaking in the contact zone, leading to the formation of a fracture focus, occurs in organosilicon coatings KO-168. For PVAC coatings, an abrupt growth of cracks is characteristic, which is preceded by its slow growth. The pseudoplastic mechanism of destruction of PVAC coatings has been established. The influence of the nature of the substrate on the change in the nature of the peeling of the coatings is considered.

Influence of Paint Coating Thickness on the Probability of Cracking

“…В работах [1][2][3] для анализа причин разрушения лакокрасочных покрытий фасадов зданий использовалась диаграмма Парето, т. е. выделились в первую очередь приоритетные факторы, которые попадают в 80 % куммулятивной кривой. Авторами установлено, что список видов разрушений покрытий, составляющих 80 % куммулятивной кривой, состоит в основном из растрескивания и отслаивания покрытий [4], однако нередко наблюдается одновременно три типа разрушения: когезионный (растрескивание), адгезионный (отслаивание) и смешанный [5][6][7][8][9][10].…”