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 degrees 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%.