Ning Zhong,Jean Baptiste Maniriho,Qianlin Wu,Xiaodong Wang,Yijia Gu,Wenge Li,Yuantao Zhao
This work was initiated with the purpose of expanding the utilization of nickel-based composite coatings, especially in wear and corrosion-related industrial applications. NiCoP coatings have long attracted scientific and engineering interest due to their enhanced mechanical properties reinforced by incorporation with a reinforcement phase. In the present study, NiCoP composite coatings reinforced with ZrB2 ceramic particles were synthesized by direct current deposition using a modified Watt's type bath. The microstructures of composite coatings were studied by x-ray diffraction analysis, energy dispersive x-ray spectroscopy, and scanning electron microscopy, respectively. The hardness and tribological properties of the composite coatings were evaluated and compared. The corrosion behaviors of the deposits were investigated using electrochemical spectroscopy and potentiodynamic polarization techniques in simulated seawater. The effect of ZrB2 content on the microstructures and mechanical properties of the composite coatings was explored and discussed. The present study indicates that there is a progressive enhancement in the hardness, corrosion resistance, and wear resistance of the composite coatings with the increase in ZrB2 loading. The NiCoP-12 g/l-ZrB2 coating possesses the highest microhardness and superior wear performance, while the NiCoP-6 g/l-ZrB2 coating exhibits the best anti-corrosion properties. The present study shows a cost-effective and feasible solution for the preparation of NiCoP protective coatings with enhanced properties, which holds great potential for industrial applications requiring wear and anti-corrosion protection.
The incorporation of highly thermally conductive ceramic materials in polymers could improve effectively the thermal conductivity of polymer matrix . In this work, Zirconium diboride (ZrB 2 ) particles with high thermal conductivity were introduced into an epoxy polymer matrix by in situ synthesis method for the improvement of thermal conductivity of epoxy matrix . The thermal conduction of epoxy composites was investigated by laser flash method and numerical analysis. The dispersive status of the fillers was characterized by transmission electron microscopy (TEM). The results showed that the thermal conductivities of epoxy resin were increased significantly due to the addition of ZrB 2 particles. The thermal conductivity of epoxy composites increases with the increase of ZrB 2 particles loading ranging from 0 wt% to 16 wt%. The enhancement of thermal conductivity exhibited a little change when the particles content exceeded 12 wt%. The influence of the temperature on the improvement of thermal conductivity was inconspicuous. The thermal conductivity of ZrB 2 /epoxy composites increased slightly with the increase of temperatures in the range of 25–100 °C. The distribution of ZrB 2 particles in the matrix affected the thermal conductivities of epoxy composites greatly. In comparison, the composites with 12 wt% ZrB 2 particles loading presented better dispersion of the particles in the epoxy matrix than those of the other composites. The thermal conductivity values of the composites at 12 wt% loading obtained by finite-element analysis (FEA) were in good agreement with the experimental value.
The tribological performance of in-situ epoxy composites reinforced with micro-sized particles of zirconium diboride (ZrB 2 ) were investigated in dry sliding conditions. The frictional heat flow in the contact areas was analyzed using finite element modeling . It was found that the dominant wear mechanisms of composites were changed from adhesive wear to abrasive wear due to the introduction of ZrB 2 particles under the imposed sliding conditions. The coefficient of friction (CoF) and coefficient of wear K of composites decreased significantly with the increase of ZrB 2 particle content. The increase in thermal conductivity due to the addition of ZrB 2 particles was proposed to contribute to the enhanced wear resistance under given sliding conditions.
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