Nano‐Engineered Basalt Fiber Composites With Halloysite Nanotubes: Durability and Drilling Behavior After Acidic Aging

ABSTRACT This study investigates the drilling performance and environmental durability of basalt fiber reinforced polymer (BRC) and halloysite nanotube (HNT) modified basalt nanocomposites (BRnC) exposed to aggressive acidic conditions (Hydrochloric acid (HCl), pH 1.5) for 70 days. The incorporation of 2 wt% HNT significantly enhanced the barrier properties of the epoxy matrix, limiting the maximum acid uptake to 2.2%, whereas the reference BRC reached 3.0% weight gain. Elemental analysis revealed that HNT modification effectively suppressed the leaching of network‐modifying ions (calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K)) and network‐forming species, such as aluminum (Al) and iron (Fe), from the basalt fibers. Specifically, Al leaching was reduced from 15,840 mg/L in BRC to 11,880 mg/L in BRnC after 56 days of exposure. Drilling experiments showed that acidic aging leads to a reduction in thrust forces due to interfacial degradation and matrix plasticization. The non‐aged BRnC exhibited the highest thrust force of approximately 200 N at 0.15 mm/rev feed rate, indicating improved structural rigidity provided by the nanotubes. Phenomenological observations through scanning electron microscopy (SEM) and digital imaging confirmed that HNTs increase the matrix tortuosity and improve the fiber–matrix interfacial integrity, thereby mitigating drilling‐induced damages such as delamination and fiber pull‐out even after prolonged chemical aging. These findings demonstrate that HNT‐modified basalt composites offer superior durability and reliable secondary processing capabilities for structural applications in harsh environments.