Thermal behaviour of La0.8Sr0.2Fe1−xGaxO3−δ (x = 0 or x = 0.3)

✍ Scribed by A. Julian; E. Juste; P.M. Geffroy; N. Tessier-Doyen; P. Del Gallo; N. Richet; T. Chartier

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 724 KB
• Volume: 29
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2009.02.016

✦ Synopsis

The thermo-mechanical behaviours of La 0.8 Sr 0.2 Fe 1-x Ga x O 3-δ (x = 0 or x = 0.3) ceramics for catalytic membrane reactors are studied up to 1100 • C under air and nitrogen atmospheres. XRD data, thermogravimetric and dilatometric analyses associated with Young's modulus measurements give a better understanding and a qualitative description of the mechanical behaviour of the perovskite materials as a function of temperature. First, a decrease of Young's modulus from room temperature to 300-400 • C is attributed to FeO 6 octahedrons distorsions of the monoclinic (or orthorhombic) phase. After phase transition, the rhombohedral phase exhibits a higher TEC and a stiffening of the perovskite structure probably due to less distorted FeO 6 octahedrons. Finally, at higher temperatures (T > 800 • C), thermogravimetric data show a weight loss attributed to oxygen departure from the perovskite structure leading to a large cell expansion.

This study presents the structural evolution of both materials and its impact on the thermal and mechanical behaviours that have to be considered for industrial uses.