Sustainable erosion‐resistant composites: Role of alkali treatment in pine fibre reinforcement

Epoxy composites reinforced with pine fibres were fabricated by hand lay‐up at fibre loadings of 4 wt.%, 7 wt.%, 10 wt.%, and 13 wt.%. The fibres were sodium hydroxide (NaOH) treated to enhance interfacial adhesion, and the composites evaluated for mechanical and erosion wear performance. At 10 wt.%, hardness, tensile, flexural, impact, and interlaminar shear strength improved by 18.6 %, 70.5 %, 100.4 %, 89.5 %, and 270.8 %, respectively, over the 4 wt.% composite. Air‐jet erosion was studied using quartz sand (≤75 μm) under steady‐state conditions. Peak erosion occurred at 60°–75° impingement angles, indicating semi‐ductile behaviour; the erosion rate decreased with fibre content up to 10 wt.%. A Taguchi L16‐ANOVA identified fibre content as the most influential parameter, followed by impact velocity, erodent feed rate, and impingement angle, while scanning electron microscopy (SEM) analysis revealed micro‐cracking, cutting, delamination, and plastic deformation. The novelty of this work lies in the combined use of NaOH‐treated Himalayan pine (Pinus roxburghii) needle fibre, a reinforcement seldom examined in erosion studies, together with integated mechanical, dynamic mechanical, and erosion characterisation across fibre loadings, and a Taguchi L16‐ANOVA framework that ranks the factors governing erosive wear and identifies 10 wt.% as the optimum loading.