FeCr-based bulk metallic glasses with enhanced wear and corrosion resistance

Seawater contains a high concentration of Cl⁻ ions, and prolonged exposure can lead to severe corrosion and wear of ship hulls, thereby increasing maintenance and operational costs. In this work, we developed a series of FeCr-based bulk metallic glasses with Cr content exceeding 30 at.%. Notably, when the Cr content reaches 30 at.%, the alloy exhibits excellent comprehensive performance, including a high glass transition temperature of 904 K and a hardness of 1429 HV. These enhancements are attributed to the increased contents of Cr-C and Cr-B bonds. Among the compositions studied, the Fe₃₇Cr₃₀W₁₀C_13.5B_7.5Y₂ alloy exhibits superior wear resistance, with a wear rate as low as 6.33 × 10⁻⁶ mm³ N⁻¹ m⁻¹. However, further increasing the Cr content to 37 at.% results in a higher wear rate of 9.17 × 10⁻⁶ mm³ N⁻¹ m⁻¹. This might be due to the reduction in indentation toughness, which increases the brittleness and promotes fatigue wear. Moreover, the Fe₃₇Cr₃₀W₁₀C_13.5B_7.5Y₂ alloy shows good corrosion resistance in a 3.5 wt% NaCl solution, with a low self-corrosion current density of 2.25 × 10⁻⁶ A/cm². Nevertheless, excessive Cr content destabilizes the passivation layer, leading to premature pitting corrosion. This degradation arises from a sharp decrease in the Cr³⁺/Cr⁶⁺ ratio during passivation and an increase in cation vacancies, which together reduce the corrosion resistance.