Relationship between load and tribological properties of B4C-hBN/TC4 pair in seawater environment

Purpose The purpose of this paper is to investigate the influence of applied load on the tribological response of the B4C-hBN/TC4 pair in seawater, and to provide a theoretical foundation for applications in ocean engineering. Design/methodology/approach The worn surface morphology was analyzed using scanning electron microscopy and 3D profilometry, while the chemical composition changes of the worn surface were examined using X-ray photoelectron spectroscopy and Raman analysis, to observe the influence of applied load on the tribological performance. In addition, the friction mechanisms were analyzed using the Hertzian and Greenwood–Williamson models. Findings The results showed that B4C-hBN composite with 30 Wt.% hBN could achieve the lowest friction coefficient (COF) under constant load. With load rising from 10 to 30 N, the COF of B4C-30wt.%hBN/TC4 pair first decreased and then increased, reaching its minimum at 20 N. At this optimal load, a continuous tribo-film was formed on the wear surface, which was primarily composed of low-shear-strength products such as Ca(OH)2, Mg(OH)2, CaCO3 and H3BO3, and could provide effective lubrication and surface protection. Originality/value This study investigates the effect of load on the tribological behavior of B4C-hBN/TC4 in seawater, reveals the lubricating role of hBN and addresses gaps in the field, offering important theoretical significance for marine engineering.