Degradation study of polymer coating: Improvement in coating weatherability testing and coating failure prediction

Effect of Hexafluorozirconic Acid Pretreatment on Cathodic Delamination of Epoxy Coatings from Steel Substrates

“…When an organic coating is physically damaged by impact, scratching, or wear and subsequently is exposed to an electrolyte, the electrolyte's access to the underlying steel substrate allows electrochemical reactions to take place at the coating/substrate interface. [1][2][3] As a result, oxygen reduction occurs with electrons released by anodic dissolution of the steel substrates in defect areas, whch results in a buildup of hydroxide ions under the coatings, which in turn degrades the adhesion between coatings and substrates through alkalization. [4][5][6] This process, called cathodic delamination, is recognized as one of the primary mechanisms of coating failures on steel.…”

Weathering of Compounded Products

“…187 The polysiloxane additive improved the clearcoat resistance against pancreatin. 188 The same samples were exposed to a 4 years field test in locations with corrosivity classified as C3 (Bandol, France) and C5M (Pipady, France). 188 The same samples were exposed to a 4 years field test in locations with corrosivity classified as C3 (Bandol, France) and C5M (Pipady, France).…”

“…192 Samples of solvent-borne anticorrosive coatings were exposed to different artificial weathering tests: a neutral salt spray test (NSS ISO 9227) and four cycles (QUV ASTM G53, ASTM D5894, ISO 20340, and a new laboratory cycle, including condensation at 45 o C for 6 days; 1 h (5 h if first time) at 50 o C+2 h at -5 o C for 1 day; 14 h at 35 o C+10 h of neutral salt spray at 23 o C (ISO 9227) for 7 days). 188 The major change during aging was assigned to plasticizer migration from the basecoat and primer binders, leading to glass transition temperature increase. 188 The major change during aging was assigned to plasticizer migration from the basecoat and primer binders, leading to glass transition temperature increase.…”

“…188 The same samples were exposed to a 4 years field test in locations with corrosivity classified as C3 (Bandol, France) and C5M (Pipady, France). 188 The new cycle correlates better with natural exposure based on the development of internal stress in the coating, probably caused by more thermal and hygroscopic cycling. 188 The new cycle correlates better with natural exposure based on the development of internal stress in the coating, probably caused by more thermal and hygroscopic cycling.…”

Degradation-based maintenance decision using stochastic filtering for systems under imperfect maintenance

“…Repairs slowing down degradation rate can be easily visualized in the context of, e.g., coating operations. In order to slow down the deteriorating process, steel structures are usually protected by certain organic coating systems (Perrin et al, 2009). The degradation level after each coating operation may or may not be changed.…”