Preparation of Sol-Gel Derived Anticorrosive Coating on Q235 Carbon Steel Substrate with Long-Term Corrosion Prevention Durability

• Published in: Materials 2019-06, Vol.12 (12), p.1960
• Main Authors: Li, Yue, Wu, Chunchun, Xue, Ming, Cai, Jiawen, Huang, Yi, Yang, Hui
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Atomic beam spectroscopy; Atomic force microscopy; Carbon steel; Carbon steels; Chemical bonds; Coating effects; Corrosion prevention; Corrosion resistance; Crosslinking; Electrochemical impedance spectroscopy; Filler materials; Industrial applications; Killed steels; Mechanical properties; Metals; Microscopy; Nanoparticles; Particle size; Protective coatings; Repair & maintenance; Salt spray tests; Scanning electron microscopy; Service life; Silica gel; Silicon dioxide; Sol-gel processes; Spectrum analysis; Spray deposition; Stainless steel; Substrates; Thickness
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12121960

Anticorrosive coatings prepared by sol-gel derived approaches have become an emergent research area in the field of corrosion prevention materials. Furthermore, enhanced coating thickness can greatly improve the barrier effect of the sol-gel coatings, thus influencing their service life in industrial applications. Here, we propose the preparation of a two-layer coating system using a low-cost sol-gel derived method. The coating structure was composed of first an underlying layer incorporated with silica and titania powder as filler and pigment materials, and a second translucent topcoat containing a colloidal silica sol-gel matrix crosslinked by methyltrimethoxysilane (MTMS). This coating system was applied on Q235 carbon steel substrate by a two-step spray deposition method, resulting in an enhanced coating thickness of around 35 μm. The physical and morphological properties of the coatings were characterized using multiple techniques, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The anticorrosion performance of the sol-gel coatings was studied by a salt spray test, outdoor exposure test and electrochemical impedance spectroscopy (EIS). Results revealed that this two-layer coating system exhibited excellent physical and anticorrosion properties, and that the topcoat played a crucial role in maintaining the barrier effect and preventing water leakage.