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Phytic acid (PA) benzotriazole composite conversion films with different concentrations of BTA were prepared by an impregnation method, and their wettability, microstructure, and corrosion resistance were studied. The results showed that when the BTA content was 1.6 wt %, the maximum water contact angle of the conversion film reached 137.5°, and the corrosion current density reached a minimum of 1.610 × 10–7 A/cm2. The salt spray and corrosive liquid environments experimental results also showed that the synergistic effect of PA and BTA was the best when the BTA concentration was 1.6 wt %. Hydrogen bonds are formed between PA chelates and BTA chelates enhancing the density of the conversion film leading to the improvement of corrosion resistance of conversion film on a copper surface with the introduction of BTA. [ABSTRACT FROM AUTHOR]

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 (icorr). 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. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) decorated by titanium dioxide (TiO2) was fabricated and introduced into the chemically bonded ceramic coatings as a nanofiller. The analysis of the results of thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) show that TiO2 has decorated on the surface of GO by chemical bonds. Furthermore, the effect of incorporating GO-TiO2 on properties of ceramic coatings was investigated. The results show that GO-TiO2 achieved a homogeneous dispersion and compatibility in ceramic matrix without obvious cracks. The potentiodynamic polarization test was conducted to investigate the influence of GO-TiO2 on the corrosion behavior. The results demonstrated that corrosion resistance of ceramic coatings remarkably enhanced by adding GO-TiO2. Furthermore, the anticorrosive mechanisms of ceramic coatings with GO-TiO2 were tentatively discussed. [ABSTRACT FROM AUTHOR]

With thermal chemical reaction, the chemically bonded ceramic coatings are prepared on A3 steel. Influence of zinc oxide on corrosion resistance of the coating is investigated by corrosion polarization analysis. It is found that the chemically bonded ceramic coatings show the outstanding corrosion resistance. In addition, the coating with zinc oxide possesses a smaller reaction rate and corrosion current density than the coating without zinc oxide. Scanning electron microscope (SEM) analysis and X-ray diffraction (XRD) analysis are conducted to find the reason. Without adding zinc oxide, AlPO is the main binding phase connecting with the particles in the coating, and the micro structure of the particles can be seen clearly. However, with adding zinc oxide, a new binding phase Zn3(PO) is found in the coating. Besides, the particles in the coating are fully covered with Zn(PO) and AlPO, and the micro structure of the particles cannot be clearly seen. The particles have a better cover with the binding phase compared with the particles without zinc oxide. Therefore, adding zinc oxide makes the coating more compact that hinders access of HO, O, and Cl to the substrate with the compact coatings, which improves the corrosion resistance of the chemically bonded ceramic coatings. [ABSTRACT FROM AUTHOR]