Sliding wear behaviors of electrodeposited nickel composite coatings containing micrometer and nanometer La2O3 particles

Micrometer and nanometer La₂O₃ particles were codeposited with nickel by electroplating from a nickel sulfamate bath. The wear behaviors of the composite coatings were evaluated sliding against AISI 1045 steel under non-lubricated conditions. It was found that the incorporation of the La₂O₃ particles enhances the microhardness and wear resistance of Ni coatings. The wear resistance of the Ni composite coating containing nano-sized La₂O₃ particles is higher than that of the Ni composite coating containing micro-sized La₂O₃ particles. The codeposition of the smaller nanometer La₂O₃ particles with Ni effectively reduces the size of Ni crystals and significantly increases the hardness of the composite coatings, resulting in significantly improved wear resistance of the nano-sized La₂O₃/Ni composite coating.