Effect of duty ratio on the performance of pulsed electrodeposition Ni-P-Al2O3-PTFE nanocomposite coatings

To improve the comprehensive performance of the material surface in the complex working environment, Ni-P-Al2O3-PTFE nanocomposite coatings were prepared by a pulsed electrodeposition process in this study. The effects of pulsed duty ratio on the microscopic morphology and mechanical properties of the prepared composite coatings were investigated. The microstructure and element content of the composite coatings were evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The microhardness, wear resistance and elastic-plastic properties of the composite coatings were analyzed by Vickers hardness tester, rotary friction and wear tester and nanoindentation tester, respectively. The results show that the introduction of pulsed current can improve the surface quality of composite coatings, a lower pulse duty ratio can increase the nucleation rate, hinder grain growth and obtain the nanocomposite coatings with sufficient grain refinement. When the pulse duty ratio is 30%, the surface morphology of composite coating is excellent, the deposition rate reaches 14.94 mu m/h, the microhardness reaches the maximum value of 671 HV, the friction coefficient reaches the minimum value of 0.0923, the elastic recovery ratio h(e)/h(max) reached the maximum value of 0.34, and the ratio of H-3/E-2 reached the maximum value of 0.046. The combination of hard Al2O3 nanoparticles and solid self-lubricating polytetrafluoroethylene (PTFE) particles can significantly improve the comprehensive performance of nanocomposite coatings, and the results of this study can provide theoretical and technical support for the preparation of multi-nanoparticle synergistic enhanced Ni-P-based composite coatings.

Automated summary

In this study, Ni-P-Al2O3-PTFE nanocomposite coatings were prepared using a pulsed electrodeposition process to improve the comprehensive performance of the material surface in a complex working environment. The effects of pulsed duty ratio on the microscopic morphology and mechanical properties of the coatings were investigated. The results showed that an appropriate pulse duty ratio could result in composite coatings with excellent surface morphology and improved performance.