Mechanical Properties of Al2TiO5 Ceramics for High Temperature Application
Sung- Soo Ryu.
The present work investigated the effects of MgO as a thermodynamic stabilizer and ZrO2 and mullite (3Al2O3·SiO2) as kinetic
stabilizers on the mechanical properties of Al2TiO5 at high temperatures. Al2TiO5 was synthesized using reaction sintering at 1500, 1550,
and 1600°C for 2 h. The mix-stabilized Al2TiO5 sintered at 1500°C showed the highest mechanical strength (138 MPa) at 1100°C, while
the mullite-only Al2TiO5 sintered at 1550°C showed a mechanical strength of only 67 MPa at 1200°C. The strength improvement
achieved at high temperatures was affected by not only secondary phase mullite to inhibit grain growth of Al2TiO5 and to improve
strength but thermodynamic stabilizer to promote synthesis Al2TiO5. The coefficient of thermal expansion of mix-stabilized Al2TiO5 decreased
with increase of sintering temperature due to its microcrack, however, that of the mullite-only Al2TiO5 was not changed because
of large number of pores.
Keywords: Aluminum titanate, high-temperature strength, low thermal expansion, stabilizers.
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