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Zinc oxide (ZnO) decorated multi-walled carbon nanotubes (MWCNTs) hybrid material was prepared to improve the tribological performance of chemically bonded ceramic coatings. TEM results reveal that ZnO has been successfully fabricated on the surface of MWCNTs. The tribological performance of the ceramic coatings with MWCNTs–ZnO hybrid material was investigated using a ball-on-disc method. The results show that the friction coefficient and wear rate of the ceramic coatings decrease with the increase of MWCNTs–ZnO hybrid material. The ceramic coatings with MWCNTs-ZnO hybrid material shows a smooth worn surface with less cracks and delamination. In addition, the worn surface of the counterpart ball shows a smaller worn area and a smooth surface. The excellent wear resistance of the ceramic coatings is attributed to the good bonding strength between MWCNTs–ZnO hybrid material and ceramic matrix. [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]

In this study, carbon fiber was modified by 3-Aminopropyl triethoxysilane (KH550) and employed as a functional filler to enhance the wear resistance of chemically bonded ceramic coatings on AISI 304L stainless steel. The chemical structure and morphology of silane-treated carbon fiber (CF) were characterized using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). It was found that the surface of CF became rough due to the grafting of KH550, which improved the bonding strength between CF and ceramic matrix. The tribological performance of the ceramic coatings with silane-treated CF was evaluated using a ball-on-disc method. The results showed that the friction coefficient and wear rate of the ceramic coatings decreased with the increase of the content of silane-treated CF. These improvements were attributed to the strong bonding strength between silane-treated CF and ceramic matrix, which could consume more fracture energy and block the diffusion pathway of cracks. This study provides new insights into the design and optimization of wear-resistant ceramic coatings reinforced with modified carbon fiber for potential engineering applications. [ABSTRACT FROM AUTHOR]

The paper investigates preparation and mechanical performances of a composite ceramic coating reinforced by graphene and multi-walled carbon nanotube. The carbon nanotube is functionalized with the carboxyl functional group (-COOH) and un-functionalized with sodium dodecyl benzene sulfonate (SDBS). The structure of the functionalized and hybrid-functionalized carbon nanotube is identified using infrared spectroscopy (FTIR analysis). The coating is brushed on the matrix and then cures under temperature lower than 250°C. The morphological and cross section features are studied by scanning electron microscopy (SEM). The distributions of hardness and fracture toughness are determined using a microhardness tester. The adhesive strength is evaluated using a universal tensile tester. The tribological properties are detected using friction wear testing machine. The experimental results show that the structure of the composite coating is compact, and both graphene and hybridtreated carbon nanotube are well dispersed. Addition of 0.2 wt % graphene and 0.2 wt % hybrid-functionalized carbon nanotube results in a prominent increase in hardness and fracture toughness. Meanwhile, the adhesive strength between the composite coating and the metallic substrate is well improved due to the high tensile strength of both graphene and carbon nanotube. Compared with pure alumina coating, the friction coefficient as well as the wear depth and width of grinding crack of the composite coating is much lower. [ABSTRACT FROM AUTHOR]