Production of phosphor bronze coatings by laser cladding

Laser cladding is a method to deposit a coating to improve the surface properties of a part or to restore the surface of worn components. Phosphor bronze is an alloy with high fatigue resistance, corrosion resistance and low coefficient of friction. So, it is employed in applications like sleeve bearings or cam followers. Laser cladding technique can be employed to generate a bronze coating over steel to improve the surface properties of elements like drive shafts or bearings. In this research work, a High Power Diode Laser was employed to generate a bronze coating on cylindrical AISI 4340 alloy steel (UNS G43400) substrates. The microstructure observed in bronze coatings is dendritic. It is formed by two phases: copper solid solution with tin (α-Cu) and Cu41Sn11 (δ-Cu). The hardness of the phosphor bronze coating is 172±12 HV, which is higher than the one reported for cast bronze.