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Improvement on thermophysical and mechanincal properties of LaMgAl11O19 magnetoplumbite by Nd2O3 and Sc2O3 co-doping.
- Source :
-
Ceramics International . Oct2021, Vol. 47 Issue 20, p28892-28903. 12p. - Publication Year :
- 2021
-
Abstract
- LaMgAl 11 O 19 -type magnetoplumbite holds great promise to be used above 1300 °C as thermal barrier coatings (TBCs), but its practical application has been restricted because of inferior thermophysical properties. Herein, we focus on optimizing the thermophysical properties of LaMgAl 11 O 19 by simultaneously substituting La3+ and Al3+ ions with Nd3+ and Sc3+ ions, respectively. Results show that the effects of co-substitution on reducing thermal conductivity are pronounced. The thermal conductivities of La 1- x Nd x MgAl 11- x Sc x O 19 (x = 0, 0.1, 0.2, 0.3) ceramics decrease progressively with dopant concentration and a lowest thermal conductivity of 2.04 W/(m·K) is achieved with x = 0.3 at 1000 °C, which is a value superior to pure LMA and even lower than YSZ. The mechanisms behind the lowered thermal conductivity are investigated. Increase of the thermal expansion coefficient is also realized (8.53 × 10â6 Kâ1 for pure LMA, 9.07 × 10â6 Kâ1 for x = 0.3, 1300 °C). Most importantly, Nd3+ and Sc3+ combination doping indeed facilitates mechanical properties of La 1- x Nd x MgAl 11- x Sc x O 19 solid solutions as well. It should be noted that Sc3+ doping at Al3+ site plays more effective role in improving thermal properties than Nd3+ does at La3+ site. This work provides a path to simultaneously integrate low thermal conductivity, good phase stability, moderate thermal expansion behavior and excellent mechanical properties on LMA for the next generation TBCs. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02728842
- Volume :
- 47
- Issue :
- 20
- Database :
- Academic Search Index
- Journal :
- Ceramics International
- Publication Type :
- Academic Journal
- Accession number :
- 152252387
- Full Text :
- https://doi.org/10.1016/j.ceramint.2021.07.050