Effect of duty ratio on properties of Ni-P-Al₂O₃-PTFE nanocomposite coatings by pulsed jet electrodeposition

In order to enhance the wear resistance and toughness of the material surface, Ni-P-Al₂O₃-PTFE nanocomposite coatings were prepared by pulsed jet electrodeposition technology, and the effect of duty ratio on the comprehensive properties of the nanocomposite coatings was studied. The surface morphology, microstructure and mechanical properties of the nanocomposite coatings were analysed by X-ray diffractometer, scanning electron microscope, energy dispersive spectrometer and nanoindenter. The results show that compared with direct-current deposition, the application of pulse current plays a positive role in the preparation process of jet electrodeposition, and with the increase of the duty ratio, the surface quality and comprehensive properties of the nanocomposite coatings first improve and then reduce. When the duty ratio is 40%, the surface morphology and particle distribution of the composite coating are uniform and dense, the content of Al and F elements reaches the maximum value of 1.12 and 0.76 wt%, the microhardness reaches the maximum value of 540 HV, the average friction coefficient and wear scar width reach the minimum value of 0.1205 and 125.04 μm, the elastic recovery ratio (h_c/h_max) reaches the maximum value of 0.40, and the ratio of microhardness to Young's modulus (H³/E²) reaches the maximum value of 0.057. At this point, the nanocomposite coating exhibits excellent wear resistance and toughness. The development of this work will promote the application of nanocomposite coatings in the field of material surface protection and strengthening. (author)