Effects of electrophoretic deposition time and heat treatment on mechanical properties of carbon nanotubes reinforced C/SiC composites

Carbon nanotubes (CNTs) were introduced into pyrolytic carbon (PyC) interface of C/SiC composites via electrophoretic deposition (EPD) and chemical vapor infiltration (CVI). The CNTs amount was controlled by the electrophoretic deposition time. The effect of CNTs content on the tensile strength and fracture work of CNTs-C/SiC composites was investigated. The mechanical properties of CNTs-C/SiC composites after heat treatment were analyzed. The results show that the strength and toughness of C/SiC composites can be greatly improved by electrodepositing CNTs into PyC interface layer. The strength of the composites are increased by 10.7%, 39.3% and 45.2% and the work of fracture are improved by 31.1%, 35.9% and 46.5%, respectively, when the deposition time is 5, 8 and 10 min. The tensile strength of the composite increases after the heat treatment at 1 800 ℃. The tensile strength of the CNTs-C/SiC composites with the heat treatment at the deposition time of 0, 8 and 10 min is improved by 64.4%, 39.4% and 49.5% respectively, compared to the samples without the heat treatment.