Weathering effect on the wear performance of epoxy powder coatings reinforced with calcium ion-exchanged amorphous silica

• Published in: Progress in organic coatings 2024-12, Vol.197, p.108837, Article 108837
• Main Authors: Fernández-Álvarez, María, Calderón-Perea, Nataly E., Bautista, Asunción, Velasco, Francisco
• Format: Article
• Language: English
• Subjects: Abrasive wear; Anticorrosive micropigments; Epoxy powder coating; Erosive wear; Ultraviolet degradation
• ISSN: 0300-9440
• DOI: 10.1016/j.porgcoat.2024.108837

Epoxy coatings generally have poor performance when used for exterior applications. After having studied the corrosion benefits obtained with calcium ion-exchanged amorphous silica pigments, the possible weathering advantages they may provide to powder coatings are analyzed in this work for the first time. For that purpose, five epoxy-based powder coatings were studied: the as-received coating (AR), and four epoxy subjected to a hot mixing process with different amounts by weight of silica anticorrosive micropigments (0 %, 1, 2 and 3 %). All epoxy coatings were degraded by ultraviolet radiation with a xenon lamp for 250 h to determine their weathering resistance. The damage suffered by each coating was evaluated quantifying their FTIR spectra, considering the carbonyls and hydroxyls formed during this type of degradation. Subsequently, studies of plastic universal hardness and abrasive and erosive wear were carried out. The results obtained show that these functionalized coatings have better mechanical and wear performance than the commercial coating after xenon light exposure. This is coherent with the fact that the non-reinforced coatings have the greatest degradation both by hydrolysis and photodegradation. After the weathering process carried out, the 3 % coating proves to have the best abrasive and erosive wear performances. Thus, the calcium ion-exchanged silica particles allow the service life of UV exposed epoxy powder coating to be extended, not only because of their anti-corrosive character but also because of their weathering stabilization properties. These findings represent a significant advancement in improving the durability of epoxy powder coatings for exterior applications. [Display omitted] •The influence of Xe irradiation on functionalized epoxy powder coatings is studied.•Anticorrosive pigments have been added to powder coatings in three amounts.•The pigments enhance the weathering resistance of the epoxy coatings.•Irradiation increases the hardness of the coatings.•The weathered coating with 2 % pigments shows the best wear performance.