Step-by-Step\nTuning of Tribological and Anticorrosion\nPerformance of Zinc Phosphate Conversion Coatings through Effective\nIntegration of Spherical P‑Doped MoS<sub>2</sub> Nanoparticles

Surface coatings with enhanced mechanical\nstability,\nimproved tribological\nperformance, and superior anticorrosion performance find immense application\nin various industrial sectors. Herein, we report the development of\nmultifunctional composite zinc phosphate coatings by the effective\nintegration of a structurally and morphologically tuned P-doped MoS<sub>2</sub> nanoparticle additive (3P–MoS<sub>2</sub>) into the\nzinc phosphate matrix to offer attractive characteristics suitable\nfor industrial applications. The integration of spherical nanoparticles\nas additive leads to the formation of homogeneous and compact coatings\nwith a densely packed crystalline microstructure having enhanced microhardness,\ndistinctive leaf-like morphology, and comparatively smooth topographical\nfeatures. The attractive lubricity of the additive (3P–MoS<sub>2</sub>), coupled with its spherical morphology, facilitates a transition\nfrom sliding to rolling friction and contributes significantly toward\nthe performance enhancement of the tuned composition of the composite\nzinc phosphate coating (0.3–PMS). Thus, the tuned 0.3–PMS\ncoating delivers the lowest specific wear rate (1.334 × 10<sup>–5</sup> mm<sup>3</sup>/Nm) and coefficient of friction (0.114)\nthat significantly outperform bare-zinc phosphate coating. Further,\nthe electrochemical corrosion study results indicate the improvement\nin corrosion resistance behavior of the composite zinc phosphate coatings\nwith reduced corrosion current density (<i>i</i><sub>corr</sub>) and charge transfer resistance (<i>R</i><sub>ct</sub>) values, as compared to the bare-zinc phosphate coating. The effect\nof passivation in conjunction with the barrier protection characteristics\nof the composite coatings induced by the optimal composition of the\nintegrated additive nanoparticles (3P–MoS<sub>2</sub>) can\nefficiently prevent the infiltration of corrosive ions and thereby\nsignificantly reduce the rate of corrosion.