Capped inhibitor-loaded halloysite nanoclay-based self-healing silica coatings for corrosion protection of mild steel. Issue 20 (15th October 2022)

• Record Type: Journal Article
• Authors: Gautam, Aarti; Siva, T.; Sathiyanarayanan, S.; Gobi, K.V.; Subasri, R.
• Is Part Of: Ceramics international. Volume 48:Issue 20(2022)
• Page Start: 30151
• Page End: 30163
• Publication Date: 2022-10-15
• Subjects: Autonomous healing -- Silica coatings -- Corrosion protection -- Mild steel -- Inhibitor -- Halloysite nanoclay; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.06.288
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The effect of polymeric nanocapsule capping in benzotriazole encapsulated into halloysite nanoclay (HNTs) dispersed into hybrid silica coatings was investigated for corrosion protection of mild steel. Optimization of the amount of inhibitor-loaded halloysite nanotubes with and without capping in the coating sol was carried out. The prepared formulations were dip-coated on mild steel substrates using dip-coater and then cured at 130 °C for 1 h. Surface morphology and elemental analysis of the nanoclay were studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. X-ray diffraction and Fourier Transform Infrared spectroscopy analyses were carried out to confirm the encapsulation and capping of the halloysite nanoclay. The anti-corrosion and autonomic-healing properties of bare and coated substrates in 3.5 wt% NaCl solution were studied using electrochemical impedance spectroscopy, potentiodynamic polarization measurements and scanning vibrating electrode technique for varying exposure times. The coatings generated from the capped inhibitor-loaded HNTs dispersed sol-gel matrix was seen to provide higher corrosion resistance when compared to uncapped HNT based silica coatings. Electrochemical studies carried out for capped inhibitor-loaded HNT based coatings have shown an increase in charge transfer resistance to 10 8 Ω cm 2 from 10 6 Ω cm 2 of uncapped inhibitor-loaded HNT based coatings.