α-SiAlON–SiC composites obtained by gas-pressure sintering and hot-pressing

Elongation of α‐SiC Particles in Spark Plasma Sintered α‐SiAlON/α‐SiC Composites

“…Both 20 and 40 wt% SiC compositions resulted in a uniform fine normal microstructure (see Figs. 3(c) and (d)) in contrast to the bimodal in the 0–5 wt% SiC compositions, in consistency with the previous reports 8–12 . In addition, as mentioned in the introduction section in those literatures both SiAlON and SiC grains lost anisotropic to form fine equiaxed microstructures, contrast to the maintenance of the self‐toughening microstructures formed by anisotropic grains in this study.…”

“…SPS may play a unique role in the microstructural development of the 0–40 wt% SiC compositions regarding the fast elongation of the α‐6H SiC in the 40 wt% SiC for the absence of the β→α‐SiC polytype transformation to grow the anisotropic SiC grains 4–7 . As evidence Santos and colleagues 8–12 tried unsuccessfully to grow either the elongated α‐SiAlON grains or SiC in the SiAlON/SiC composites by various sintering techniques such as pressureless sintering, gas pressure sintering, or hot pressing for hours at 1900°–2100°C. The rapid SPS heating presumably increased the driving force for mass transportation and anisotropically grew the selected α‐SiAlON and α‐6H SiC grains by avoiding server impinging until the final microstructure was obtained.…”

“…3(c) and (d)) in contrast to the bimodal in the 0-5 wt% SiC compositions, in consistency with the previous reports. [8][9][10][11][12] In addition, as mentioned in the introduction section in those literatures both SiAlON and SiC grains lost anisotropic to form fine equiaxed microstructures, contrast to the maintenance of the self-toughening microstructures formed by anisotropic grains in this study. When the SiC content was increased gradually to 20 wt% or over, the a-SiC grains were elongated to give an impressive morphology transformation from equiaxed to anisotropic.…”

“…[1][2][3][4][5][6][7] Regarding possible higher microstructure control flexibility through phase transformations, in addition to better corrosion resistance and mechanical properties such as higher hardness and creep resistance, numerous literatures have attempted at synthesizing SiAlON/silicon carbide ceramic composites in which self-toughening microstructures were pursued. However, the coexistent SiAlON and SiC always sabotaged the self-toughening microstructure [8][9][10][11][12] by depriving the anisotropic growth of either a-SiAlON or SiC grains, especially when the contents of the a-SiAlON and SiC were comparably equal, to destroy the self-reinforcing effects exhibited in both monolithic ceramics. In the few documents devoted to this composite system, [8][9][10][11][12] the SiAlON, either aor b-SiAlON was remarkably refined into very small equiaxed grains by the coexistent SiC particles.…”

Abrasive wear behavior of SiCp–Sialon composite refractories

“…The wear resistance of composites can be improved by increasing the fracture toughness [8,9]. At present, various methods, such as a reaction-bonded process, [10][11][12] improving sintering methods, [13,14] introducing the second phase, [15][16][17] microstructure design, [18,19] adding sintering additives [20][21][22]. have been proposed to reinforce the fracture toughness of ceramics.…”