Thermal-assisted cold sintering study of Al2O3 ceramics: Enabled with a soluble γ-Al2O3 intermediate phase

Shenglin Kang, Xuetong Zhao, Jing Guo, Jie Liang, Jianjie Sun, Yang Yang, Lijun Yang, Ruijin Liao, Clive A. Randall

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Thermal-assisted cold sintering process (TA-CSP) has been applied to fabricate high dense α-Al2O3 ceramics with submicron grain sizes. The α-Al2O3 (80 wt%) and γ-Al2O3 (20 wt%) powders are firstly mixed and then cold sintered at 300 °C to produce a green bulk with a relatively high density of ∼ 86.9 %, and then later a second heat treatment (800–1350 °C) is applied to finally fabricate (∼ 98 % dense) α-Al2O3 ceramics with grain sizes of 720 nm. A microstructural analysis with XRD and TEM suggests that the TA-CSP samples not only complete the final densification but also drive a phase transition of γ-Al2O3 to α-Al2O3. To put into perspective the Hardness and Young's modulus of TA-CSP samples reach ∼ 14 GPa and ∼ 335 GPa, respectively, which is comparable to conventional sintered samples processed at higher temperatures of 1500–1700 °C. Therefore, it is feasible to utilize TA-CSP to prepare α-Al2O3 ceramics with small grain sizes at low sintering temperatures.

Original languageEnglish (US)
Pages (from-to)478-485
Number of pages8
JournalJournal of the European Ceramic Society
Volume43
Issue number2
DOIs
StatePublished - Feb 2023

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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