Bioinspired Water‐Lubricated Bearing Materials of Marine Propulsion for Tribological Properties Advancements

ABSTRACT The environmentally friendly water‐lubricated bearing is one of the most important constituents of the marine propulsion system. However, the water‐lubricated bearings still face the challenge of poor tribological properties under harsh working conditions such as dry frictional and heavy load, resulting in unreliable working performance. In this case, the Lignum vitae wood biomaterial, which is the earliest water‐lubricated bearing material due to its excellent self‐lubricating properties, is used as the bionic object. Three different kinds of bionic fibers, including thermoplastic polyurethanes (TPU) fibers, silicone oil/TPU core‐shell fibers, and polydimethylsiloxane (PDMS)/TPU core‐shell fibers, are designed, and the bionic materials are manufactured further. The Lignum vitae wood sample (LVS) is used as a contrast for evaluation. The tribological experimental results indicate that the bionic material samples present far better tribological properties than the LVS under dry frictional and heavy‐load water‐lubricated working conditions. Among all the samples, the PDMS/TPU fibrous membranes bionic material samples (PTM) under parallel to fibers sliding direction present the best tribological properties due to their unique soft‐hard gradient structure. Specifically, the PTM achieves the maximum reduction of 73.0% and 98.7% in friction coefficient and wear volume compared with the LVS. The knowledge gained in this study provides a novel route to improve the tribological properties of water‐lubricated bearing materials.