Cavitation pit evolution process of epoxy and polyurea coatings on mortar substrates

• Published in: Ultrasonics sonochemistry Vol. 104; p. 106813
• Main Authors: Huang, Caisheng, He, Xiaolong, Zhang, Jianmin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2024; Elsevier
• Subjects: Cavitation erosion; Damage evolution; Epoxy coating; Polyurea coating; Damage evolution; Epoxy coating; Polyurea coating; Cavitation erosion
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2024.106813

•Cavitation erosion of different polymer coatings on mortar are investigated.•The water wedges and radial cracks led to the detaching of the epoxy polymer coating.•The introduction of intermediate epoxy mortar layer delays cavitation pits formation.•The elastic deformation of polyurea reduced the cavitation erosion probability. This study focuses on unraveling the failure mechanisms of three distinct polymer-coating structures applied to mortar substrates: an epoxy coating (MEP1), an epoxy coating with an intermediate epoxy mortar layer (MEP2), and a polyurea coating with an intermediate epoxy mortar layer (MPU). Ultrasonic cavitation experiments are conducted to investigate the initial stages of cavitation erosion. The damaged surfaces of these three coating structures are meticulously investigated and characterized. An in-depth analysis is performed on the distribution characteristics of cavitation pits and the evolutionary patterns of these pits. The results indicate that the introduction of epoxy mortar as an intermediate layer significantly enhances the material’s cavitation resistance by improving its energy absorption capacity. This enhancement delays the formation of cavitation pits on the coating surface. Additionally, the superior adhesive properties of the intermediate epoxy mortar with the mortar substrate prevent direct cavitation erosion from forming on the substrate, even when brittleness failure occurs and coating erosion is observed on the surface epoxy polymer. The polyurea coatings demonstrate exceptional elastic–plastic deformation capabilities. When combined with the intermediate epoxy mortar layer, MPU can withstand prolonged and repetitive cavitation impacts, resulting in minimal coating erosion.