Densification of nanocrystalline Y2O3 ceramic powder by spark plasma sintering

Rachman Chaim (1) , Amit Shlayer (1) , Claude Estournès (2)

1 Technion - Israel Institute of Technology [Haifa]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Nanocrystalline Y2O3 powders with 18 nm crystallite size were sintered using spark plasma sintering (SPS) at different conditions between 1100 and 1600 ◦C. Dense specimens were fabricated at 100MPa and 1400 ◦C for 5 min duration. A maximum in density was observed at 1400 ◦C. The grain size continuously increased with the SPS temperature into the micrometer size range. The maximum in density arises from competition between densification and grain growth. Retarded densification above 1400 ◦C is associated with enhanced grain growth that resulted in residual pores within the grains. Analysis of the grain growth kinetics resulted in activation energy of 150 kJ mol−1 and associated diffusion coefficients higher by 103 than expected for Y3+ grain boundary diffusion. The enhanced diffusion may be explained by combined surface diffusion and particle coarsening during the heating up with grain boundary diffusion at the SPS temperature.

Mots clés: Spark plasma sintering; Nanocrystalline; Y2O3; Grain growth; Densification

Domaines: Matériaux

Rachman Chaim, Amit Shlayer, Claude Estournès. Densification of nanocrystalline Y2O3 ceramic powder by spark plasma sintering. Journal of the European Ceramic Society, 2009, 29 (1), pp.91-98. ⟨10.1016/j.jeurceramsoc.2008.05.043⟩. ⟨hal-03572304⟩