Enhanced Load Transfer by Ceramic Coating in Carbon Nanotubes Reinforced Al Matrix Composites

Achieving appropriate interfacial bonding while avoiding structural damage is the foremost concern in fabricating high-performance carbon nanotube (CNT)/Al matrix composites. In this work, a ceramic coating strategy was developed to enhance the interfacial strength of CNT/Al composites. A continuous SiO2 layer, approximately 50 nm in thickness, was uniformly coated on the surface of acid-treated CNTs using the sol-gel method. Through the combination of hetero-agglomeration process, spark plasma sintering, and hot extrusion, the SiO2@CNTs experienced limited structural damage and remained dispersed and singly aligned in the Al matrix. Due to the presence of the amorphous SiO2 layer between the CNTs and the Al matrix, the CNTs were polygonally deformed and free from interfacial reactions. Consequently, the 2.0 wt.% SiO2@CNT/Al composites exhibited an increased mechanical performance, indicating enhanced load transfer at the CNT-Al interfaces due to the ceramic coating.