Investigation of Seawater Environment Effects on Basalt Fiber-Reinforced Epoxy Composites and the Influence of Surface Treatment on Performance

The paper investigates the impact of seawater (salt water) exposure on various characteristics of basalt fiber-reinforced epoxy composites (BFREC). It also examines the effects of hydrogen peroxide and sodium carbonate treatments on water absorption, mechanical properties, and tribological behavior. Structural analysis using Fourier transform infrared spectroscopy (FTIR) and morphological assessment via scanning electron microscopy (SEM) revealed an increased density of functional groups (OH, methyl, Si-C, and Si-O) on basalt fiber surfaces post-treatment. As compared to untreated basalt fiber (UTB), the chemical treatment of basalt fiber with sodium carbonate notably enhanced the mechanical interlocking between the matrix and the fibers, resulting in a 26.74% increase in Young's modulus, a 15.14% increase in tensile strength, and a 9.52% increase in hardness. Similarly, chemical treatment with hydrogen peroxide yielded significant improvements, including a 31.11% increase in tensile strength, a 45.51% increase in Young's modulus, and a 28.57% increase in hardness. Sodium carbonate-treated BFREC exhibited a 19.76% reduction in water absorption and a 15.91% decrease in coefficient of friction, with slight reductions in tensile strength and modulus of elasticity after 45 days. Hydrogen peroxide-treated BFREC showed a 26.97% decrease in water absorption and a 21.83% decrease in coefficient of friction, with small reductions in modulus of elasticity and tensile strength over the same period. SEM imaging has been used for worn surface analysis.