Microstructure and Wear Characteristics of Nickel-Based Coatings Produced via Laser Cladding on 6061 Aluminum Alloy

The nickel (Ni)-based alloy cladding layers on the surface of 6061 aluminum alloy are fabricated successfully using an optimized laser cladding process. An analysis has been conducted to compare the influence of two types of Ni-based powders on the phase composition, macroscopic morphology and microstructure of the cladding layers. The study also elucidates the micro-hardness and friction property of the cladding layers fabricated by two types of Ni-based powders. The results reveal that phases including Al3Ni, Al3Ni2, and α-Al are formed in the pure Ni cladding layer. Nonetheless, in the Ni–Cr–B–Si cladding layer, a new phase characterized by needle-shaped Cr7C3 is observed. Mechanical properties characterization of the cladding layers reveals a notable improvement in microhardness and friction properties compared to the 6061 aluminum alloy substrate. The best properties are achieved in the Ni–Cr–B–Si cladded layer, which demonstrates a microhardness of 714 HV, almost 8.1 times superior to that of the substrate. Its friction and wear rate is merely 21% of that of the base aluminum. Our results are expected to provide significant insights into the design and production of aluminum materials with great resistance to wear.