Effect of pulsed current-assisted CMT welding parameters on friction and wear properties and electrochemical corrosion performance of heterogeneous structure composites

The interfacial integrity of Babbitt alloy bushings is critical to the service life of sliding bearings operating under extreme conditions, including cyclic shock loads, seawater ingress, and prolonged boundary lubrication. Conventional bonding techniques often result in interfacial voids and thermal stress cracking, limiting performance. To address these issues, a novel joining process combining low-heat-input cold metal transfer (CMT) with pulsed current has been developed for Babbitt alloy bushings. The pulsed current generates electromagnetic forces (Lorentz force) that stir the molten pool, promoting heterogeneous nucleation, refining grain structure, and reducing defects. Reflecting real-world bearing applications, this study focuses on the friction-wear performance and localized corrosion behavior in a simulated marine environment at 30 °C / 168 hours. The results demonstrate that pulse-assisted CMT welding parameters significantly influence the tribological and electrochemical properties of the Babbitt alloy. The sample produced with 10-pulse series exhibited the lowest friction coefficient (0.27) and the lowest wear rate (2.95×10 -6 mm 3 /(N·m)). Meanwhile, the 13-pulse sample showed superior corrosion resistance, presenting the highest electrochemical impedance, the most positive self-corrosion potential, and the lowest corrosion rate (1.96×10 -7 A·cm -2 ). This work provides metallurgical strategies aimed at improving the reliability of next-generation offshore wind turbine bearings.