Optimization of tribological properties and corrosion resistance of MAO coatings on LY12 aluminum alloy by co-doping with graphite particles and in situ formation of zinc phosphate
Micro-arc oxidation (MAO) coatings can enhance the wear and corrosion resistance of aluminum alloys, but the high coefficient of friction and surface pores can lead to failure in the field. In this study, zinc acetate and graphite particles are introduced to the electrolyte to form corrosion-resistant and lubricating MAO coatings on the LY12 aluminum alloy. Zinc phosphate nanocrystals formed in situ are uniformly distributed in the amorphous coating, while the extrinsic graphite is mainly located in the amorphous structure. Compared to the aluminum alloy substrate, the friction coefficient of the optimal MAO coating decreases to ∼0.2, and the wear rate decreases by nearly 10 times. Zinc phosphate nanocrystals generated in situ in the coatings release Zn 2+ during corrosion attack to cover the vulnerable weak corrosion areas around the pores. The corrosion resistance is improved significantly, as manifested by the increase of the corrosion potential from −1.290 V to −0.811 V and the decrease of the corrosion current density from 3.172 × 10 −6 A cm −2 to 4.320 × 10 −10 A cm −2 . The co-doped MAO coatings have better wear and corrosion resistance and are more suitable than the LY12 alloy in many engineering applications.
危险品化学品经营许可证（带存储）