Silica-containing coatings for corrosion protection

Coatings represent one of the most widely employed strategies for mitigating metal corrosion, yet their long-term performance is often compromised by inherent structural defects and permeability to aggressive species. While traditional filler-reinforced coatings enhance barrier properties and pigmented coatings systems can additionally provide active protection, however, in an uncontrolled way, recent advances in smart materials have enabled the development of self-healing systems capable of providing active corrosion inhibition exactly when needed. This review comprehensively examines the multifaceted role of silica-based fillers—spanning pristine, modified, and container-type structures—in the design of high-performance corrosion protection coatings. We comprehensively analyze coating fabrication technologies, the barrier-enhancing mechanisms of silica fillers, and advanced strategies for synthesizing and functionalizing silica micro/nano-containers to achieve stimuli-responsive release. Special emphasis is placed on “gatekeeper” systems that enable on-demand, localized delivery of inhibitors in response to corrosion-related triggers. By integrating discussions on both physical barrier enhancement and active self-healing functionality, this work provides a unified perspective on silica-based coating design. Furthermore, we critically assess current challenges, including filler dispersion, release kinetics control, and scalability, and propose future research directions aimed at advancing the practical application of intelligent silica-containing coatings for extended metallic structure durability.