Tribological and magnetic behaviour of Ni-P coating modified with NiO nanoparticles.

Nickel oxide nanoparticles with the size of 218, 73, and 50 nm were added to Ni-P electroless coating to create NiO@Ni-P nanoparticle reinforced composite coating on a brass substrate. The nanoparticles were synthesized by the green synthesis method, using Artemisia dracunculus extract. The coatings had amorphous structure and nodular morphology. The results of Tafel and EIS tests showed that the coating containing nickel oxide nanoparticles with an average size of 73 nm, had the highest corrosion resistance. The results of the tribocorrosion test under open circuit potential condition revealed Ni-P-(73 nm)NiO coating had the highest tribocorrosion resistance. Heat treatment at 400°C caused considerable improvement in the saturation and remnant magnetization of the composite coating, the value of saturation and remnant magnetization increased from 5 and 0.1 emu/g for simple Ni-P coating to 12 and 2 emu/g for NiO@Ni-P coating respectively, and the coercive field of the samples also enhanced. [ABSTRACT FROM AUTHOR]