MICROSTRUCTURE AND WEAR RESISTANCE OF LASER-TREATED Ni–P–Al2O3 ELECTROLESS DEPOSITION COMPOSITE COATING

Abstract

A uniform Ni–P–Al2O3 electroless plating layer was produced on medium carbon steel and then scanned by high-power continuous wave CO2 laser beam. The entire coating is divided into three regions: laser-strengthened region, transition zone, and heat-affected zone. The strengthened coating shows good performance characterized by uniform components and refined microstructures. The main phase is comprised of Ni3P with some non-equilibrium phases. The reinforced particles, Al2O3 , are homogeneously dispersed in the coating. Its abrasive resistance also increases because of the Al2O3 particles.