Determination of structural and mechanical properties of multilayer graphene added silicon nitride-based composites

Silicon nitride based nanocomposites have been prepared with different amount (1 and 3 wt%) of multilayer graphene (MLG) as well as exfoliated graphite nanoplatelets (xGnP) and nano graphene platelets (Angstron) in comparison. The microstructure and mechanical properties of the graphene reinforced silicon nitride based composite materials have been investigated. Homogeneous distribution of the MLG additives have been observed on the fracture surface of the sintered material. The scanning electron microscopy examinations showed that graphene platelets are inducing porosity in matrix. The bending strength and elastic modulus of MLG/Si3N4 composites showed enhanced values compared to the other graphene added silicon nitride ceramic composites. These observations may be explained by the different type and quality of the starting materials and by the dispersion grade of graphene platelets having direct impact to the resulting density of the sintered samples.