Preparation of eco-friendly natural rosin-based SiO2–NH2@GO hybrid sealant and study on corrosion resistance of Fe-based amorphous coating for steel substrate

Sealing treatment is an effective method to prolong the service life of Fe-based amorphous coatings for steel substrates. Common sealants always have the disadvantages of releasing amounts of volatile organic compounds (VOC) and are expensive, prompting researchers to develop an eco-friendly, low cost and high-performance sealant. However, their simultaneous improvement is restricted by some inevitable contradictions among them. Herein, natural rosin was introduced as a sealing material and an eco-friendly natural rosin-based SiO2–NH2@GO hybrid sealant was successfully prepared by the sol-gel method. In addition, the functional nanocomposite SiO2–NH2@GO was added to the hybrid sealant system to achieve the purpose of extending the service life of the sealant. The filling efficiency, adhesion, thermal stability and long-term corrosion resistance of hybrid sealants were investigated. The study showed that the adhesion of the hybrid sealant to the Fe-based amorphous coating was improved by 10.59% after adding the nanocomposite. The hybrid sealant reaches maximum thermal decomposition at 414.3 °C. The corrosion current density (icorr) of the sample NSG-0.5‰ still decreased by about two orders of magnitude after immersion for 672 h (0#, icorr = 1.39 × 10−4 A/cm2; NSG-0.5‰, icorr = 1.51 × 10−6 A/cm2). Full immersion experiments explore the failure process of hybrid sealants, where corrosion always tends to propagate with unmelted particles. The hybrid sealant prepared has the advantages of being eco-friendly and low cost, and provides a specific preparation process, which provides a new direction for the development of the sealant.