Fabrication of ultrafine-grained alumina ceramics by two different fast sintering methods

The preparation of ultrafine-grained alumina ceramics by the fast sintering technique Self-propagating High-temperature Synthesis plus Quick Pressing (SHS-QP) method and spark plasma sintering (SPS) technique was reported. The effects of different heating rates (SHS-QP-1600 degrees C/min, SPS-200 degrees C/min) on the preparation of ultrafine structure were compared. The densification and grain growth as a function of sintering time and temperature were discussed. Within a short sintering time (<3 min), the full-dense alumina with ultrafine-grained structure was obtained by SHS-QP at 1550 degrees C under 100 MPa. By SPS, the sintering temperature was lower (1200 degrees C) than that of SHS-QP. The differences in densification parameters were explained by analyzing the thermodynamics of sintering process. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.