Nanostructured Co₃O₄-graced 3D carbon felts for improved mechanical interlocking in epoxy composites: morphological and mechanical/tribological optimization

This study utilizes mechanical interlocking as a method to improve the adhesion between the 3D carbon felt foam (CFs) and the epoxy matrix (EP). Hydrothermally, Co₃O₄ nanoarrays in nanostrips, nanowires, nanoprisms, and nanostars were added to CFs surfaces. Pure 3D carbon fiber-epoxy composites had 62.7% higher storage modulus and 7.8% higher glass transition temperature than pure epoxy. The 3D carbon fiber/epoxy composite with Co₃O₄ nanowires has a storage modulus of 5297 MPa and a Tg of 148.4 °C, which is higher than that of pure 3D CFs and other nanocomposites. Compared to pure 3D CFs/ EP, Co₃O₄ nanowires boost flexural strength by 75.0%. Nano-strip, nano-prismatic, and nanostar composites improve 53.6%, 21.4%, and 11.43%, respectively. Pure 3D CFs boost epoxy matrix impact strength to 174.6%. The impact strength of the Co₃O₄ nano-wire@CFs/EP composite is 45.6% higher than that of the 3D CFs/EP composite. Nano-strip, nano-prismatic, and nano-star modifications are 31.2%, 19.5%, and 2.5%. 3D CFs/EP composites have a 69 MPa initial tensile strength. However, Co₃O₄ nano-wires increase tensile strength by 73% to 130 MPa. Nano-strip, nano-prismatic, and nanostar composites outperform 3D CFs/EP by 68%, 33%, and 7%, respectively. In 3D CFs/EP composites, Co₃O₄ nanowires reduce wear by 50.0% and friction by 27.9%.