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A metal matrix composite coating reinforced by ZrC-ZrB₂ particulates has been successfully fabricated utilizing the in situ reaction of Zr, B₄C and Fe pre-placed mixed powders by gas tungsten arc welding (GTAW) cladding process. Various volume fraction of ZrC-ZrB₂ particulates composite coatings were produced through cladding different weight ratios of Zr+B₄C (30%, 50%, 70%) to improve the wear resistance of AISI1020 steel substrate. The Microstructure of the coating was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrum (EDS), meantime microhardness and wear resistance at room temperature of the composite coating were examined by means of Microhardness Tester and Wear Tester, respectively. The results show that the main phases of the composite coating obtained by GTAW are ZrC, ZrB₂ and α-Fe, ZrC exhibits hexahedron and petal shapes, ZrC-ZrB₂ compound presents acicular and clubbed forms. With the increase of content of Zr+B₄C, the maximum volume fraction of ZrC-ZrB₂ particulates can reach 16.5%, microhardness is up to 1300HV, and wear resistance is about twenty times higher than that of AISI1020 steel substrate.

Using an electrospinning device, we determined the optimal conditions for producing nanofibers from a 10% solution of Co–AN. These conditions involved applying a 15kV voltage to the anode, which was connected to the syringe containing the solution, and maintaining a distance of 12–15cm from the needle tip to the collector screen (cathode). The filament diameter (d) ranged from 0.2 to 0.5mm. This setup allowed the formation of nanofibers under the cover. The electrolysis process was conducted for varying durations, ranging from 4 to 14h, while applying currents of 2mA, 4mA, and 8mA. At 4mA and 8mA, a substantial portion (approximately 65–70%) of the macroions in the solution reassembled on the electrode surfaces. These images clearly illustrate the restoration of macroions on the electrode surfaces, achieved through electron exchange processes. This phenomenon results in the combination of macroions and their neutralization, leading to the formation of a composite coating on the titanium, iron plate, and rods.

The MoS₂ particles were coated with polystyrene and can be written as PS/MoS₂ hereinafter. Ni–PS/MoS₂ coatings and Ni–MoS₂ coatings were produced by PC electrodeposition technique. The surface morphology of Ni–PS/MoS₂ coating was examined and compared with those of Ni–MoS₂ coating. The effect of particle concentrations on the volume percent of particles incorporated in the coatings was investigated. And the microhardness of coatings was also investigated. Results show that the surface morphology of Ni–PS/MoS₂ coating is regular and the thickness of coating is uniform. The introduction of MoS₂ to coatings caused dendritic growth. The surface morphology of Ni–MoS₂ coating is irregular. With the same particles concentration in bath, the volume percent of PS/MoS₂ particles incorporated in the composite coatings was higher than those of MoS₂ particles; and the microhardness of Ni–PS/MoS₂ coating was higher than those of Ni–MoS₂ coating.

The MoS₂ particles were coated with Al₂O₃ ratio varying from 5 to 50 wt.% content. Ni–MoS₂/Al₂O₃ composite coatings were prepared by means of pulse electrodeposition. The dependence of preferential orientation index and corrosion properties of these composite coatings was investigated in relation to the Al₂O₃ ratio in MoS₂/Al₂O₃ particles. Polarization measurements have been used to evaluate corrosion resistance performance of coating. The Ni–MoS₂/50 wt.%Al₂O₃ coatings showed the highest corrosion resistance compared with Ni–MoS₂/5 wt.%Al₂O₃, Ni–MoS₂/10 wt.%Al₂O₃, and Ni–MoS₂/30 wt.%Al₂O₃ coatings. Thus, it is understood that the increase of ratio of Al₂O₃ in MoS₂/Al₂O₃ composite particle improves the corrosion efficiency of coating. These Al₂O₃ act as inert physical barriers to the initiation and development of corrosion defect, hence improve the corrosion resistance of the coating.

In situ titanium carbide reinforced iron-based composite coating was deposited on mild carbon steel using laser surface engineering (LSE) with ferrotitanium and graphite as precursor. The microstructure and phase constituents of the deposited coating were characterized. Formation mechanism of titanium carbide crystal in the composite coating was elucidated by correlating the morphology of titanium carbide and the thermal cycle experienced by the precursor during the laser treatment. It was demonstrated that titanium carbide was formed in situ as a result of the metallurgical reaction between ferrotitanium and graphite following a liquid-precipitation route. Different morphologies of titanium carbide crystal (dendrite and fishbone) correspond to the primary and eutectic titanium carbide respectively.

Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol–gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO₂ gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.

NiCrBSi alloy coatings are widely used in wear and corrosion protection at higher temperature. As a primary hard phase forming element, B element can effectively improve the coating hardness. In this study, the low coefficient of friction of BN with three ratios (10%, 20%, and 30%) was added in order to reduce the wear rate and provide additional B element. The NiCrBSi/h-BN composite coatings were successfully prepared on a cast-iron substrate using supersonic air-plasma spray technology. The phase constitution, microstructure characterization, and microhardness of the coatings before and after oxyacetylene flame remelting were investigated by means of scanning electron microscope (SEM), X-ray diffraction, and energy dispersive analysis of X-ray techniques, respectively. The wear resistance of composite coatings was also tested in this paper. It was found that the microstructure was well refined by remelting treatment and this was beneficial for the adherence between the coating and the substrate, which was nearly 33MPa. The wear resistance of the NiCrBSi alloy coating was also improved with the increasing component of h-BN in remelted samples. When the h-BN content reached 30%, the friction coefficient decreased to 0.38 for the remelted coating. The effect of the remelting process on the anti-abrasive property and extension of the material’s wear life was quite important.

In order to enhance the corrosion resistance of mooring chain, the composite coatings are carried out on the surface of 22MnCrNiMo steel for mooring chain by double-pulsed electrodeposition technology using centrifugal force in the rotating device. The microstructure and anti-corrosion performance of the composite coatings have been investigated experimentally. This paper mainly focuses on the experimental work to determine the structural characteristics and corrosion resistance of composite coatings in the presence of nano-SiC. The results show that the presence of nano-SiC has a significant effect on the preparation of composite coating during the process. The surface of the coating becomes compact and smooth at a moderate concentration of nano-SiC particles. Furthermore, the best corrosion resistance of the composite coatings can be obtained when the concentration of nano-SiC particles is 2.0g.L${}^{-1}$ after salt spray treatment.

Two kinds of composite coatings, Zn${}_{45}$Al${}_{35}$Mg₅ZnO${}_{15}$ and Zn${}_{65}$Al${}_{15}$Mg₅ZnO${}_{15}$, were prepared on steel matrix (Q235) by cold spraying. The Zn, Al, Mg, and ZnO in raw materials were calculated by percentage of mass. The morphology of the original coating was observed by scanning electron microscopy (SEM) and characterized by energy dispersive spectroscopy (EDS). It was found that the microstructures of Zn${}_{45}$Al${}_{35}$Mg₅ZnO${}_{15}$ and Zn${}_{65}$Al${}_{15}$Mg₅ZnO${}_{15}$ composite coatings prepared by cold spraying were compact without oxidation products, and the plastic deformation of powder particles was significant. The friction and wear test data of the two coatings showed that the Zn${}_{45}$Al${}_{35}$Mg₅ZnO${}_{15}$ coating had longer-lasting protective properties and wear resistance under the same conditions. Neutral salt spray test (NSS) and electrochemical accelerated corrosion test were carried out on samples at different time periods. The results of samples’ corrosion microstructure and electrochemical curves showed that Zn${}_{45}$Al${}_{35}$Mg₅ZnO${}_{15}$ and Zn${}_{65}$Al${}_{15}$Mg₅ZnO${}_{15}$ have good electrochemical protection performance, and Zn${}_{45}$Al${}_{35}$Mg₅ZnO${}_{15}$ coating has better protection effect.

To improve hydroxapatite (HA) coatings on the titanium substrate, HA/Ti composite was formed on substrates using Radio-frequency (RF) plasma spraying process, as this composite layer may reduce the residual stress due to the large difference in the liner thermal expansion coefficient between the substrate and HA. HA/Ti composite was prepared by controlled feeding of HA and Ti powder, as the composition of coatings becomes HA-rich toward the outmost. Coating layer was evaluated by SEM-EDX, XRD and tensile testing. Orientation in c-axis direction of prepared coatings was observed from X-ray diffraction patterns. HA/Ti composite coating gave a higher adhesive (tensile) strength over 10 MPa than direct HA coatings on substrate.