Spark plasma sintering of Si₃N₄/multilayer graphene composites

Abstract

Mulitlayer graphene reinforced silicon nitride composites were prepared by spark plasma sintering to investigate the effect of the graphene addition on mechanical properties. The composites contained multilayer graphene (MLG) in various (0, 1, 3 and 5 wt%) content. Significantly higher fracture toughness of 8.0 MPa m 1/2 was obtained at 1% MLG content, however, on further increasing the graphene content the toughness did not increase, but dropped to the value of the monolithic silicon nitride. The maximum hardness of 18.8 MPa was also obtained at 1% MLG, while at higher MLG contents it gradually decreased.

Spark plasma sintering of graphene reinforced silicon carbide ceramics

“…According to the literature, MLG addition may induce porosity in the matrix and thus, reduces the hardness [14,27]. Our results did not support these observations: in samples sintered at 1750°C and above, no pore formation was observed either in the SEM, or in the TEM micrographs.…”

“…We found previously that the fracture toughness of Si 3 N 4 ceramic had been improved by 60% by adding 1 wt% MLG to the matrix. However, the increase of graphene content above 3 wt% made the sintered ceramics more porous and led to inferior mechanical properties [27].…”

Alumina-graphene nanocomposite coatings fabricated by suspension high velocity oxy-fuel thermal spraying for ultra-low-wear

“…It has also been shown that fracture toughness of bulk alumina composites can be increased by the addition of 0.5% by weight GNPs, from a mean of~3.5 to~5.5 MPa.m 1/2 [25]. A similar significant increase has been shown in bulk silicon nitride/GNP composites at 1% loading, followed by a drop in fracture toughness at higher wt.% [26]. In the case of HVOF sprayed coatings, the splat-based lamellar structure means that mechanical properties are highly orientation dependent, and it is likely that mechanical properties including fracture toughness may be increased across layers of the coating between which GNPs are present.…”

Microstructures and mechanical properties of graphene platelets-reinforced spark plasma sintered tantalum diboride-silicon carbide composites

“…Further, different nanoscale carbon forms like carbon nanotubes (CNTs), graphene nanoplatelet (GNPs) addition is also prefered to improve fracture toughness of this material in recent years. Especially, graphene-based materials have more attention for the reinforcement of ceramics, due to their extraordinary thermal, electrical and mechanical properties [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Graphene is well known two-dimensional (2D) material which is an allotrope of carbon consisting of a single layer of strong in-plane covalent bonds between adjacent carbon atoms. Excellent high fracture strength (125 GPa), high young modulus (1 TPa), superior thermal conductivity (5000 W/mK) properties, it is considered to be a popular candidate material as the second phase of ceramic matrix composites.…”

“…Excellent high fracture strength (125 GPa), high young modulus (1 TPa), superior thermal conductivity (5000 W/mK) properties, it is considered to be a popular candidate material as the second phase of ceramic matrix composites. Recently, there were many studies are obtained to focus on the addition of Graphene Platelets (GPL) in the ceramic matrix composites such as AlN [15][16][17] Al2O3 [19,20], Si3N4 [21][22][23][24][25],…”