Aluminum Titanate (Al2TiO5) ceramics: complementary Al and Ti K-XAS studies

N.M. RENDTORFF; L. ANDRINI; R. MOREIRA TOJA; A. VIOLINI; M. R. GAUNA; M. S. CONCONI; F. REQUEJO

CAMPINAS

Encuentro; 26th RAU ANNUAL USERS MEETING LNLS/CNPEM; 2016

LNLS-CNPEM

Aluminum titanate (Al2TiO5) ceramics are excellent thermal shock-resistant materials due to their unique combination of low thermal expansion and low Young?s modulus. These are adequate for insulating and severe thermomechanical applications [1]. Based in X-Ray and neutron diffraction studies, Al2TiO5 was found to be one of several materials, which are isomorphous with the mineralpseudobrookite (Fe2TiO5) [2]. In this structure, each Al3+ or Ti4+ cations are surrounded by six oxygen ions forming distorted oxygen octahedral. Apparently, these AlO6 or TiO6 octahedra form (0 0 1) oriented double chains weakly bonded by shared edges. This structural feature might be responsible for the strong thermal expansion anisotropy, which generates localized internal stresses to cause severe micro-cracking.In this study we present an Al-K XANES and a Ti-K XANES/EXAFS study of two different aluminum titanates: one obtained from the calcination (1500 °C) of Alumina and Anatase [1], and another from commercial powder (industrial grade). Complementary XRD - Rietveld analysis wasalso performed for long-range order studies.Spectra features obtained for the two different samples were described and compared. No important differences were observed between both studied powders. In agreement with the mentioned experimental evidence, the detected local structure consists in distorted octahedral sites in both cases.