Interface Modification Of Carbon/Carbon Composite By Graphene Coating

Carbon/carbon composite material is a novel type of high-performance composite.Because of its special components, it is of unique performances in many aspects such aslow density, low thermal expansion coefficient, excellent mechanical properties at hightemperature, thermal shock and high temperature ablation and chemical resistance. So ithas great potential application not only in the field of aerospace engineering, but also inthe civilian area.In this thesis, we focus on Interface modification of Carbon-Carbon composite bygraphene/asphaltum and graphene oxide coatings. We want to establish the relationshipbetween the structure and performance through the characterization of interfacialproperties of C/C composite in order to develop the theoretical basis for the process ofcomposite.Reinforced fiber block was prepared with fine weave pierced method and modifiedby graphene/asphaltum coating and graphene solution under ultrasonic condition. Atlast, impregnation and Carbonization of Carbon/Carbon composite were completedunder the condition of nitrogen atmosphere and high pressure.Surface Morphology of carbon fiber was characterized by SEM, AFM. We foundthat with the increasement of graphene content, the depth of grooves on the surface offibers became shallow. But the amount and diameter of particles on the surface of fibersincreased evidently. Tensil performance tests demonstrated that mechanical strength offibers modified by graphene/asphltum coatings decreased slightly, while the mechanicalstrength of fibers modified by graphene solution was about3.65GPa as well asnon-modified fibers.The interfacial shear strength of the modified carbon-carbon composite wasimproved significantly, which was investigated by Push Out Test System. With theincreasement of graphene percentage, IFSS will decrease at the same time.Flexural strength test indicated: in the terms of C/C composite modified bygraphene/asphaltum, the flexural strength of sample with minimum concentration ofgraphene has been improved by up to approximately150%. While the samples whosecoating concentrations are0.02and0.03have increased by7%and1%respectively.There is the same trend for the samples modified by graphene oxide coations as well asthe samples treated by graphene/asphaltum coating.