High-Temperature Protective Behavior of Glass-Ceramic Self-Peeling Coatings Modified by Graphene Oxide

In the paper, the glass-ceramic self-peeling coatings modified by graphene oxide (GO) were developed on the surface of Q235 steel to enhance its high-temperature oxidation resistance by utilizing GO prepared by different modified methods as fillers. The high-temperature protective behavior of the coatings was studied using isothermal holding at 850 degrees C. The phase composition and microstructure of the coatings were investigated using X-ray diffraction, field emission scanning electron microscopy, and energy-dispersive spectroscopy. The results indicate that the weight gain curves at 850 degrees C follow a parabolic trend. Compared to uncoated samples, the oxide-layer thicknesses of samples with GC, GO, A-GO, and F-GO coatings are reduced by 75.54, 88.20, 91.41, and 96.24%, respectively. Among them, the F-GO coating exhibits the best protective performance in the given system. This is due to the gradual formation of the [SiO4]4- network layer and the production of B2O3 and Na4SiO4 during the high-temperature isothermal holding process. This significantly enhances the coating's compactness and blocks oxygen from interacting with the substrate. Moreover, unlike the linear increasing trend observed in uncoated samples, the weight gain curve of the coated samples follows a parabolic law. ZrO2 also widens the disparity between the linear expansion coefficients of the substrate and coating, thereby enhancing the coating's self-peeling abilities during the cooling process.