Back to Search
Start Over
Control of multiphase evolution and Al-deficiency in reactive-sintered MoAlB ceramics with excessive Al.
- Source :
-
Journal of the European Ceramic Society . Oct2022, Vol. 42 Issue 13, p5505-5514. 10p. - Publication Year :
- 2022
-
Abstract
- MoAlB is a ternary boride of MAB phases with strong resistance to oxidation and ablation at service temperature, thanks to preferential Al diffusion to form a protective oxide scale. However, excessive Al were often necessary in sintering of MoAlB ceramics, suggesting that a liquid-phase densification might occur thus leading to complex microstructures. By quantitative SEM analysis, ~17 mol.% Al 2 O 3 phase was found common in MoAlB ceramics. The liquid-phase of Al-Mo-B-O facilitates the direct conversion from MoB to MoAlB before in situ formation of Al 2 O 3. An intermediate Mo 3 Al 8 phase competes with layered conversion, which limits the insertion rate of Al into B-B layers of MoB to form abundant Al-deficient stacking-faults. Intermetallic Mo 3 Al 8 phase precipitates further in the intergranular regions parallel to the crystallization of Al 2 O 3 , leaving the reprecipitation of remaining Al. Both layered-conversion and intergranular oxides can improve ablation behavior for MoAlB ceramics, as well as fracture toughness and compressive strength. [Display omitted] [ABSTRACT FROM AUTHOR]
- Subjects :
- *CERAMICS
*ALUMINUM oxide
*FRACTURE toughness
Subjects
Details
- Language :
- English
- ISSN :
- 09552219
- Volume :
- 42
- Issue :
- 13
- Database :
- Academic Search Index
- Journal :
- Journal of the European Ceramic Society
- Publication Type :
- Academic Journal
- Accession number :
- 158056878
- Full Text :
- https://doi.org/10.1016/j.jeurceramsoc.2022.06.038