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

Abstract

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.