Improvement of the Tribological Properties and Corrosion Resistance of Epoxy–PTFE Composite Coating by Nanoparticle Modification

• Main Authors: Lixia Ying, Yunlong Wu, Chongyang Nie, Chunxi Wu, Guixiang Wang
• Format: Article
• Language: English
• Published: MDPI AG 2021-12-01
• Series: Coatings
• Subjects: composite coating; epoxy–PTFE; modified TiO₂; tribological properties; corrosion resistance
• Online Access: https://www.mdpi.com/2079-6412/11/1/10

In order to meet the requirements of high corrosion resistance, wear resistance, and self-lubrication of composite coatings for marine applications, epoxy matrix composite coatings containing PTFE and TiO₂ nanoparticles were prepared on the steel substrate. With silane coupling agent KH570 (CH₂=C(CH₃)COOC₃H₆Si(OCH₃)₃), titanium dioxide nanoparticles were modified, and organic functional groups were grafted on their surface to improve their dispersion and interface compatibility in the epoxy matrix. Then, the section morphology, tribological, and anticorrosion properties of prepared coatings, including pure epoxy, epoxy–PTFE, and the composite coating with unmodified and modified TiO₂, respectively, were fully characterized by scanning electron microscopy, friction–abrasion testing machine, and an electrochemical workstation. The analytical results show that the modified TiO₂ nanoparticles are able to improve the epoxy–PTFE composite coating’s mechanical properties of epoxy–PTFE composite coating including section toughness, hardness, and binding force. With the synergistic action of the friction reduction of PTFE and dispersion enhancement of TiO₂ nanoparticles, the dry friction coefficient decreases by more than 73%. Simultaneously, modified titanium dioxide will not have much influence on the water contact angles of the coating. A larger water contact angle and uniform and compact microstructure make the composite coating incorporated modified TiO₂ nanoparticles show excellent anti-corrosion ability, which has the minimum corrosion current density of 1.688 × 10⁻⁷ A·cm⁻².