Mechanical properties of nanostructured silicon carbide consolidated by spark plasma sintering

Processing and mechanical characterisation of monolithic silicon carbide ceramic consolidated by spark plasma sintering (SPS)

“…Maitre et al [9] fabricated SiC ceramic at 2223 K withoutasintering additive by applying 100 MPa of pressure, which yielded relative density values higher than 97.5 %. Loretta et al [24] indicated the conventional values for monolithicSiC ceramics are about 3-4MPa ·m 1/2 .The fracture toughness values which were obtainedinour study are in agreement withthe fracture toughness values formonolithic SiC ceramics. Forthe sample SPSed at 2073 Kw hile applying8 0MPa of pressure, the Vickersh ardness valuew as measured as 28.5 GPa.…”

“…As the sinteringt emperature increasedt o 2223 K, the Vickersh ardness value reached3 1.9 GPa. It is also noted that adecrease in toughness is correlated to areduced efficiency of crack deflection and crack bridging mechanisms [24]. Table 3s howst he influence of the sinteringp arameters on the fracture toughness of the sparkplasma sintered SiC ceramics.…”

“…Using the the hightemperature properties of the graphite die (thermal conductivity 100 Wm -1 )which was utilised in our experiments, the temperature difference between the centre and the edge of a5cm diameter die as afunction of surface temperature was calculated according to Eq. Loretta et al [24] reported that 50 MPa of pressure was applied at the beginning of the SPS cycles, the optimal applied load (130 MPa) was applied above 1273 K, which yielded ar elative density of 88.7 %SPSed at 2223 Kwith a5-minutesoaking time. The temperature differencew as obtained as 262 Ka nd 346 Ka tasurface temperature of 2073 Ka nd 2223 K, respectively.…”

“…Forthe sample SPSed at 2073 Kw hile applying8 0MPa of pressure, the Vickersh ardness valuew as measured as 28.5 GPa. Loretta et al [24] indicated that fracture toughness values varied between 2-3 MPa ·m 1/2 and are related to the grain size of the starting b -SiC nano powder. It was concludedthat ahigher sinteringtemperature and pressure led to an increase in the Vickersh ardness of the SiC ceramicsdue to accelerated densification results in the value of the relative density.…”

Electrical and thermal properties of SiC–AlN ceramics without sintering additives

“…SiC ceramics show better mechanical properties, excellent oxidation and corrosion resistances at high temperatures, but relatively poor electrically insulating properties [1][2][3][4][5][6][7][8][9][10]. In contrast, AlN ceramics exhibit generally higher thermal conductivity and better electrically insulating properties but relatively poor mechanical properties [11][12][13][14][15][16][17].…”