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 language||English (US)|
|Number of pages||8|
|Journal||Journal of the European Ceramic Society|
|State||Published - Feb 2023|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry