Enhancement of fiber–matrix adhesion in carbon fiber reinforced Al-matrix composites with an optimized electroless plating process

Abstract Coating is the most common method to offer better wettability between carbon fibers (CFs) and metal matrix of the composites. An optimal electroless Ni plating process was studied in this paper to improve the interfacial adhesion of CF reinforced Al-matrix composites. By using Pd-colloid activation, the typical island-like agglomeration on the coating surface was significantly eliminated, providing a Rq reduction of 56.5%. Applying strong-oxidizing mixed acid (SMA) etching provided larger adhesion force (140.53 nN) and interfacial shear strength (IFSS) (35.1 MPa) than that of the original process (53.72 nN and 31.1 MPa), which can be attributed to rougher surface and larger numbers of carboxyl functional groups on CF surface. By combining these processes, the adhesion force further increased to 207.99 nN with improved IFSS to 40.9 MPa, and Rq was reduced by 72.1%. The ultimate tensile strength (UTS) of the composites increased to 140 MPa, which is 35.9% higher than that with CFs by original method.