Effect of boriding on tribocorrosion behaviour of HSLA offshore mooring chain steel

This study explores the transformative potential of boriding to enhance the tribocorrosion resistance of mooring chain steel for offshore environments. The boride layers formed at various temperatures (800 °C, 900 °C, and 1000 °C) for 1 h, revealing high hardness (17–21 GPa). X-ray diffraction confirmed dual-phase FeB and Fe2B borides, contributing to superior mechanical properties. Energy-dispersive X-ray spectroscopy showed clear phase boundaries. Potentiodynamic data demonstrated improved corrosion and tribocorrosion resistance, particularly at higher boriding temperatures. Mechanical effects played a pivotal role in tribocorrosion behaviour, emphasizing the need to optimize boriding process temperatures. Electrochemical impedance spectroscopy highlights the 900 °C-1 h sample as offering excellent corrosion resistance. This study underscores boriding's potential to enhance the tribocorrosion resistance of offshore mooring chain steel. [Display omitted] •Cl ions, cracks, and stress worsen the coating's tribocorrosion susceptibility.•The mechanical effects were decisive in wear-corrosion synergism.•The passive layer reduced the friction coefficient.•Borided steel showed significantly lower corrosion rates.•Optimizing boriding temperature can further enhance tribocorrosion resistance.