Process optimization of jet electrodeposition Ni-Co-P alloy coating using response surface methodology and the tribological behavior of Ni-Co-P nanocomposite coatings.

A novel Ni-Co-P alloy coating and Ni-Co-P nanocomposite coating were prepared by jet electrodeposition. The influence of jet electrodeposition processing parameters on the microhardness and wear track width of the Ni-Co-P alloy coating was investigated. Additionally, the cross-section morphology, EDS spectra, XRD patterns, microhardness and wear resistance of the coatings under the optimum jet electrodeposition parameters were evaluated. The BBD analysis results revealed that the established mathematical model was reliable. Furthermore, the optimum Ni-Co-P alloy coating parameters optimized through the response surface method were as follows: jet voltage: 12.14 V, plating solution temperature: 61.60 °C, reciprocating sweep speed: 173.19 mm·s, jet gap: 2.05 mm, pulse frequency: 4.06 kHz and duty cycle: 0.81. Under the optimum jet electrodeposition parameters, the results revealed that the significant influence of nano BN(h) and AlO particles on the coatings' thickness, Co contents, crystallite size, microhardness and wear resistance of Ni-Co-P nanocomposite coating. In addition, compared with the Ni-Co-P alloy coating and Ni-Co-P-BN(h) nanocomposite coating, the Ni-Co-P-AlO composite coating exhibited a larger thickness (18.16 µm) and Co element contents (39.51 wt·%), a smaller crystallite size (16.440 nm), a higher microhardness (676.5 HV), a more excellent wear resistance (402.9 µm).