Development of calcium stabilized nitrogen rich α-sialon ceramics along the Si3N4:1/2Ca3N2:3AlN line using spark plasma sintering


Calcium stabilized nitrogen rich sialon ceramics having a general formula of CaxSi12-2xAl2xN16 with x value (x is the solubility of cation Ca in α-sialon structure) in the range of 0.2–2.2 for compositions lying along the Si3N4:1/2Ca3N2:3AlN line were synthesized using nano/submicron size starting powder precursors and spark plasma sintering (SPS) technique. The development of calcium stabilized nitrogen rich sialon ceramics at a significantly low sintering temperature of 1500 °C (typically reported a temperature of 1700 °C or greater) remains to be the highlight of the present study. The SPS processed sialons were characterized for their microstructure, phase and compositional analysis, and physical and mechanical properties. Furthermore, a correlation was developed between the lattice parameters and the content (x) of the alkaline metal cation in the α-sialon phase. Well-densified single-phase nitrogen rich α-sialon ceramics were achieved in the range of 0.53(3) ⩽ x ⩽ 1.27(3). A nitrogen rich α-sialon sample possessing a maximum hardness of 22.4 GPa and fracture toughness of 6.1 MPa·m1/2 was developed.


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The authors would like to acknowledge the support provided by both King Fahd University of Petroleum and Minerals, Saudi Arabia, and the University of Sharjah, United Arab Emirates.

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Correspondence to T. Laoui or A. S. Hakeem.

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Ahmed, B.A., Laoui, T. & Hakeem, A.S. Development of calcium stabilized nitrogen rich α-sialon ceramics along the Si3N4:1/2Ca3N2:3AlN line using spark plasma sintering. J Adv Ceram 9, 606–616 (2020).

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  • nitrogen rich sialon ceramics
  • α-sialon
  • calcium sialons
  • spark plasma sintering (SPS)
  • liquid phase sintering