Comparative investigation of microstructural evolution, phase formation, mechanical performance, wear and corrosion behavior of Ni–Co-, W- and AlN-reinforced laser-cladded coatings on ASTM C283 steel

Abstract

Laser cladding has emerged as an effective surface engineering technique for enhancing the durability of carbon steels operating in aggressive environments. In this study, the effects of Ni–Co, W, and AlN laser-cladded coatings on the microstructure, phase evolution, mechanical properties, tribological behavior, and corrosion resistance of ASTM C283 steel are systematically investigated and compared. Laser processing produced dense, metallurgically bonded coatings with distinct microstructural characteristics. Scanning electron microscopy revealed a homogeneous cellular–dendritic structure for the Ni–Co coating, coarse tungsten-rich regions for the W coating, and a highly refined compact morphology for the AlN composite coating. X-ray diffraction confirmed the formation of α-Fe, γ-Ni, W, and hexagonal AlN phases, with the average crystallite size decreasing from 38.14 nm for the laser re-melted substrate to 29.18 nm, 31.92 nm, and 25.78 nm for the Ni–Co, W, and AlN coatings, respectively. Atomic force microscopy further demonstrated significant grain refinement and reduced surface roughness in the AlN coating. Mechanical testing showed that the average Vickers hardness increased from 286.1 HV for the re-melted substrate to 821.8 HV (Ni–Co), 811.7 HV (W), and 956.4 HV (AlN). Correspondingly, the wear rate decreased from 11.8 × 10^-6 g.mm^-3 to 8.0 × 10^-6 g.mm^-3, 9.1 × 10^-6 g.mm^-3, and 5.8 × 10^-6 g.mm^-3, respectively. Electrochemical polarization measurements in 3.5 wt.% NaCl solution demonstrated a progressive improvement in corrosion resistance, with the corrosion current density decreasing from 14.82 μA.cm^-2 for the re-melted substrate to 5.73 μA.cm^-2 (Ni–Co), 4.91 μA.cm^-2 (W), and 1.86 μA.cm^-2 (AlN), while the polarization resistance increased from 2.84 to 8.37, 10.42, and 26.74 kΩ·cm², respectively. The AlN coating exhibited the highest corrosion protection efficiency (87.4%) and the lowest corrosion rate (0.022 mm.year^-1). Overall, the results establish a strong structure–property relationship and demonstrate that AlN-reinforced laser cladding provides the most effective combination of microstructural refinement, mechanical strengthening, wear resistance, and corrosion protection for ASTM C283 steel, making it a promising surface modification strategy for demanding industrial and marine applications.