Design a new type of composite coating of functionalized hydroxyapatite platelets-composite benzotriazole/epoxy resin with excellent anti-corrosion performance

Metal corrosion poses a significant challenge to the sustainable development of industrial society, leading to substantial economic losses and safety risks. Epoxy coatings are widely used for corrosion protection, but their performance is limited by inherent defects, such as micropores and poor long-term durability. In this study, mesoporous hydroxyapatite platelets (mHAp) were synthesized via a hydrothermal method and sequentially modified with an aminosilane coupling agent (3-Aminopropyltrimethoxysilane (KH540)) and the corrosion inhibitor (benzotriazole (BTA)) to develop a functional nanofiller (KH540-mHAp@BTA). The successful synthesis and modification were confirmed by TEM, BET, FT-IR, XRD, XPS, SEM, and TGA. The modified nanofiller was incorporated into an epoxy resin (EP) to fabricate a new type of composite coating. Electrochemical impedance spectroscopy (EIS) and scratch tests showed that the KH540-mHAp@BTA/EP coating exhibited superior corrosion resistance, maintaining a high low-frequency impedance modulus (>10 8  Ω·cm 2 ) after 30 days of immersion in a 3.5 wt% NaCl solution. The coating also showed excellent dispersion, interfacial compatibility, and active protection capability due to the sustained release of BTA. This work highlights the potential of functionalized hydroxyapatite platelets as an efficient nanofiller for advanced anti-corrosion coatings.