Spark plasma sintering of alumina/yttria‐doped silicon carbide

Abstract

Silicon carbide possesses exceptional mechanical and thermal properties, but its densification by conventional sintering is often very difficult. In the present work, silicon carbide was consolidated by spark plasma sintering in the presence of alumina and yttria. The results pointed out that the use of a single oxide does not enhance the sintering kinetics significantly, while the contemporaneous addition of both oxides has a beneficial effect on densification, with a relative density increase of about 10%. Interestingly, the oxide doping allows to double the room‐temperature flexural strength.

Enhancing the density of silicon carbide with the addition of nitrate-based additives

“…The liquid phase acts as a path for the SiC particle diffusion, enhancing the densification. The other additives that are effective for the sintering of SiC are Y2O3-SiO2, Al2O3-Y2O3-MgO, Al2O3-Y2O3-CaO, Sc2O3, Ho2O3, Yb2O3, Al2O3-RE2O3 [11][12][13][14][15][16][17][18][19][20][21]. Certainly, one of the key factors that is important in the liquid phase sintering is the homogeneous distribution of the liquid phase, which corresponds to the particle size of the additives [22].…”

Mechanical properties of SiC‐C‐B4C composites with different carbon additives produced by pressureless sintering

“…Additives such as La 2 O 3 , CaO, Y 2 O 3, and Al 2 O 3 are also used in this system. [40][41][42] SiC is known as one of the covalent materials with the highest hardness. However, hardness is a complex characteristic that includes elastic and plastic deformation, the onset and propagation of cracks, and the development of new surfaces.…”

“…In the liquid phase sintering, the presence of the liquid phase facilitates mass transfer and reduces the sinter temperature; However, the components prepared using this method have a lower hardness than the solid phase. Additives such as La 2 O 3 , CaO, Y 2 O 3, and Al 2 O 3 are also used in this system 40‐42 …”