Strengthening effect of α-ZrP nanosheet inclusions on corrosion resistance and wear resistance of NiP deposits

Ni-P/α-ZrP composite coatings were successfully prepared by electroless plating, in which α-ZrP nanosheets were synthesized by reflow method. The surface morphology, element composition, structure and valence composition of the composite coating were analyzed by SEM, EDS, XRD and XPS, respectively. In the reciprocating friction experiment and electrochemical test, the corrosion and wear behaviour of the composite coatings were analyzed. The results show that α-ZrP nanosheets can significantly improve the corrosion and wear resistance of Ni P alloys. With the enrichment of α-ZrP nanosheets, the properties of coatings showed a tendency of increasing first and then slightly decreasing. Ni-P/α-ZrP (1.00 g/L) coating has the lowest porosity and the best corrosion resistance, and its corrosion rate (6.01 × 10 −3  mm/a) is about 1/5 of that of pure Ni P coating (3.12 × 10 −2  mm/a). Ni-P/α-ZrP (1.50 g/L) coating has the best wear performance, its average coefficient of friction (COF) is reduced from 0.568 to 0.167, and the specific wear rate is reduced from 7.13 ± 0.42 (× 10 −6 ) to 0.36 ± 0.06 (× 10 −6 ) (about 1/20 of pure Ni P coating).