Comparative Investigation of the Tribological and Electrochemical Behaviors of Laser‐Clad Iron‐Based, Nickel‐Based, and Cobalt‐Based Alloys on 38CrMoAl Steel: Implications for Enhancing Extruder Screw Performance

This study systematically evaluates the tribological and electrochemical properties of eight commercial alloy powders—Fe‐based (Fe5A, Fe9A), Co‐based (Co20, CoSF20, Co701), and Ni‐based (Ni60, Ni60 + 10%WC, Ni60 + 35%(Ni)WC)—deposited on 38CrMoAl steel via laser cladding, with the aim of enhancing extruder screw performance. Comprehensive analyses of microstructure, phase composition, microhardness, wear behavior, and corrosion resistance were conducted. Results indicate that all coatings exhibited higher microhardness than the substrate (475 HV0.1), with Fe5A (953 HV0.1) and Ni60 + 35%(Ni)WC (931 HV0.1) showing the highest values. Fe5A demonstrated the lowest wear rate (1.1 × 10 − 5 mm 3 /(N m)) due to its high carbon content and refined cellular structure, while Co‐based coatings suffered from higher wear rates. Electrochemically, CoSF20 exhibited superior corrosion resistance ( I corr = 0.45 μA cm −2 ), whereas Fe5A showed the poorest performance ( I corr = 8.99 μA cm −2 ). In Ni‐based coatings, increased WC content improved hardness and wear resistance but reduced corrosion resistance due to microgalvanic effects. This work provides a scientific basis for selecting laser‐clad alloys to improve the service life of plastic extruder screws.