High mechanical properties of β-SiAlON/TiC0.3N0.7 ceramic composite prepared by pressureless spark plasma sintering

• Published in: Journal of Asian Ceramic Societies Vol. 9; no. 1; pp. 393 - 403
• Main Authors: Li, J.Q., Chen, Q.Z., Lan, Y.L., Zhang, C.H., Li, Y., Hu, L.P., Liu, F.S., Ao, W.Q., Xie, H.P.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.01.2021; Taylor & Francis Group
• Subjects: ceramic composites; mechanical properties; pressureless spark plasma sintering; Β-SiAlON
• ISSN: 2187-0764
• DOI: 10.1080/21870764.2021.1874642

β-SiAlON/TiC 0.3 N 0.7 composites containing 2.0-7.5 wt.% TiC 0.3 N 0.7 are prepared by pressureless spark plasma sintering (SPS) with Al 2 O 3 -AlN-Y 2 O 3 additives. The TiC 0.3 N 0.7 phase particles are homogeneously dispersed in the β-SiAlON matrix. The reaction between the sample and the graphite mold can be avoided during the pressureless SPS. The β-SiAlON/TiC 0.3 N 0.7 composite with 5 wt.% TiC 0.3 N 0.7 , fabricated at 1550°C, exhibits a high density of 3.28 g cm −3 (98% relative density), high Vickers hardness of 14.53 GPa, and high fracture toughness of 7.20 MPa m 1/2 . By further SPS under a pressure of 24 MPa at 1400 o C, these properties are enhanced to a higher density of 3.32 g cm −3 (full density), higher Vickers hardness of 15.87 GPa, and higher fracture toughness of 7.44 MPa m 1/2 . Obviously, the fracture toughness of the as-prepared β-SiAlON/TiC 0.3 N 0.7 composites is apparently higher than those of the reported β-SiAlON-based ceramic composites prepared by pressurized SPS, which is mainly attributed to the highly dense microstructures of the interlocking lath β-SiAlON grains and the uniformly distributed TiC 0.3 N 0.7 particles, and the disappearance of the oriented ununiform stress caused by uniaxial pressure in normal pressurized SPS. Accordingly, the pressureless SPS could be a potential technique for the fabrication of high-performance β-SiAlON matrix composites.