Composite plating of Ni–P–Al2O3 in two steps and its anti-wear performance

A composite coating of Ni–P–Al2O3 containing 50.0 vol.% of dispersed alumina particles along with approximately 8.9 wt.% (23.4 vol.%) of phosphorus into a nickel matrix was prepared by the proposed ‘Two-Step’ technique. This technique involves the electrophoretic deposition of a uniform film of alumina particles on a Ni–P-coated copper substrate in the first step followed by the electroless nickel deposition in the second step. The particle incorporated composite coatings exhibited the better anti-wear performance than the particle-free coatings. Heat treatment of these coatings deposited from an electroless bath showed the increased wear resistance of the coating due to the crystallization of hard Ni3P alloy from the amorphous Ni–P meta-stable phase. However, the referenced electrodeposited coatings exhibited the better anti-wear performance than the electrolessly deposited corresponding coatings in the present investigation.