CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Al/Ti -K-edge XANES local structure of Aluminum titanate (Al2TiO5) ceramics
Autor/es:
MARÍA AGUSTINA VIOLINI; FÉLIX REQUEJO; RAMIRO MOREIRA TOJA; MARÍA SUSANA CONCONI; LEANDRO ADRINI; MATÍAS GAUNA; NICOLÁS RENDTORFF
Reunión:
Congreso; LNLS 26th Annual Users? Meeting (RAU); 2016
Resumen:
Aluminum titanate (Al2TiO5) ceramics are excellent thermal shock-resistant materials on account of their unique combination of low thermal expansion and low Young?s modulus, which, allows for applications as an insulating material in engine components [1]. Based in X-Ray and neutron diffraction studies, Al2TiO5 was found to be one of several materials which are isomorphous with the mineral pseudobrookite (Fe2TiO5) [2]. In this structure, each Al3+ or Ti4+ cations are surrounded by six oxygen ions forming distorted oxygen octahedral. These AlO6 or TiO6 octahedra form (0 0 1) oriented double chains weakly bonded by shared edges. This structural feature is responsible for the strong thermal expansion anisotropy which generates localized internal stresses to cause severe microcracking. In this study we present an Al-K XANES and a Ti-K XANES Study of two different aluminum titanates: one obtained from the calcination (1500 °C) of Alumina and Anatase [1], and a commercial powder. These were compared with other well-known Aluminum and Titanium sites. XRD - Rietveld analysis was performed as well. Spectra features were described and compared. No important differences were observed between both studied powders. In agreement with the mentioned experimental evidence, the detected local structure consisted in distorted octahedral sites in both cases.