Growth control and wettability of Ni–P microcone coatings synthesized by electroless deposition

Micro/nano structures on metal surfaces were widely used in many fields due to their unique appearance and morphology. This study presented a simple and environmentally friendly electroless deposition method utilizing sodium hypophosphite to synthesize Ni-P microcone coatings. A systematic investigation was conducted on the effects of key process parameters on coating morphology, P content, and crystalline orientation. The results demonstrate that Ni-P coatings with different morphologies can be obtained by adjusting the process parameters. Crucially, the formation of these microcones was found to require a low phosphorus content of approximately 3.5 wt.%. And the Ni-P microcone coating exhibited a strong preference orientation of Ni(1 1 1). Based on the microscopic observation of the microcone structure and crystallographic analysis, it was suggested that the growth mechanism of Ni-P microcone coatings may be explained by the screw dislocation theory. The microcone-structured surface exhibited a water contact angle of up to 127°, significantly higher than that of flat Ni-P coatings (<110°), demonstrating the efficacy of the microstructure in enhancing surface hydrophobicity. This work provides a viable and scalable strategy for fabricating functional Ni-P microcone coatings.