Improvement of interface between Al and short carbon fibers by α-Al2O3 coatings deposited by sol–gel technology

This paper describes an investigation on an improvement of the interface between Al and short carbon fibers (SCFs) with α-Al2O3 coating by sol–gel technology. The composites of Al/uncoated SCFs and Al/α-Al2O3-**coated SCFs were fabricated successfully by vacuum press infiltration. The formation of α-Al2O3 coating during calcination was analysed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Scanning electron microscopy (SEM), energy-dispersive analysis of X-ray (EDAX) and transmission electron microscope (TEM) were used to observe the coated SCFs and the interface of composites. The results showed that the average thickness of the α-Al2O3 coating was about 200–250 nm and the formation of Al4C3 at the interface between Al matrix and SCFs was controlled by the α-Al2O3 coatings.