GO-Al2O3 nanohybrids to enhance the anticorrosion performance of chemically bonded ceramic coatings

In this study, nano-alumina/graphene oxide (GO-Al2O3) nanohybrids were synthesized and incorporated into a ceramic matrix to enhance the anticorrosion performance of chemically bonded ceramic coatings. The interaction between GO and nano-Al2O3 was investigated using Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy. Results showed that nano-Al2O3 was successfully decorated on the surface of GO through chemical bonds, which improved the bonding strength between GO and the ceramic matrix through the reaction of the aluminum phosphate binder with nano-Al2O3. The unique structures of the GO-Al2O3 nanohybrids endowed the ceramic coatings with superior anticorrosion properties as compared to the untreated substrate and pure ceramic coatings. The best corrosion resistance of coatings was achieved when the content of the GO-Al2O3 nanohybrids was 0.6 wt%, which led to the highest protection efficiency (93.4%) and the smallest corrosion current (i(corr)). The improvement in the corrosion resistance of the ceramic coatings was attributed to the excellent compatibility and dispersibility of the GO-Al2O3 nanohybrids in the ceramic matrix. In addition, the greater bonding strength between the GO-Al2O3 nanohybrids and ceramic matrix could enable more fracture energy to be consumed. This in turn could block or change the diffusion pathway of cracks, resulting in higher corrosion resistance.