Method of protection of a substrate made of steel or aluminum alloy against corrosion, which makes it possible to contribute the tribological properties, and the substrate obtained.

摘要

Corrosion protection of a steel or aluminum sheet and imparting predetermined tribological properties involves depositing a composite coating of thickness above 3 microns on the substrate. The coating comprises at least one single-phase zinc-nickel (Zn-Ni) matrix containing dispersed particles selected according to the desired tribological properties. The Ni content of the matrix is 12-20%. Preferred Features: In order to impart tribological properties of hardness and resistance to abrasion and wear to the substrate, the dispersed particles are ceramic particles of hardness higher than that of the matrix. The average size D50 of the ceramic particles is 0.01-5 microns. The ceramic particles are selected from carbides, especially silicon carbide (SiC), and oxides, especially alumina (Al2O3) or zirconia (ZrO2). In order to impart tribological properties of lubrication to the substrate, the dispersed particles are organic polymer particles or mineral particles possessing lubricating properties. The average size D50 of the organic polymer particles is 0.01-5 microns, The organic polymer particles are polytetrafluoroethylene (PTFE) particles. The mineral particles are selected from sulfides, oxides, nitrides, in particular molybdenum disulfide (MoS2), and boron nitride (BN). In order to impart tribological properties of hardness, resistance to abrasion and wear, and lubrication to the substrate, the dispersed particles comprise ceramic particles of hardness higher than that of the matrix, and organic polymer particles or mineral particles possessing lubricating properties. The thickness of the Zn-Ni matrix is preferably 5-30 microns. The amount of the particles dispersed in the matrix is 1-20 volume %. Independent claims are given for a steel or aluminum alloy substrate having a coating obtained by the above process.