Improved Thermal Stability of Y2O3 or Fe2O3 Doped Aluminium Titanate
One of the main problem encountered in application of A12TiO5, for thermal insulation purpose, is its thermal instability in the temperature interval 900°–1200°C. Dissociation occurs with α-A12O3 and rutile formation accompained with a permanent volume increase which correspond a decay of mechanical and physical properties. A purpose of this work was to investigate the effect of 5wt% Y2O3 or 5wt% Fe2O3 addition on the structural stability of β-Al2TiO5 aged at 1000°c for several length of time. Results indicate that Fe2O3 is more effective than Y2O3 in this aspect. After 1500 hours iron oxide doped aluminium titanate shows zero decomposition, meanwhile yttria doped A12TiO5 after 350 hours has 2% decomposition and after 500 hours already 35% of the ceramic material is decomposed. ether properties, like coefficient of thermal expansion, flexural strength, Young’s modulus, etc. were also checked and results, indicate that all characteristics of the materials deteriorate obviously, when decomposition occurs, but also when the material remains unaltered respect to crystalline phases. A certain decay in characteristics happen during thermal aging in both cases.
Unable to display preview. Download preview PDF.
- 2.Demaestri, P.P, Giachello, A, Martinengo, P.C, and Majani, C, Influence of some oxides on the thermal characteristics of stoichiometric A12TiO5, Proc. of First European Ceramic Society Conference, 18–23 June 1989; Maastricht, 2, 57–63.Google Scholar
- 3.Byrne, W.P, Morrel, R, and Lawson, J, Thermal expansion characterization and thermal stability of aluminium titanate, Proc. Science of Ceramics 14, 7–9 September 1987, canterbury (England).Google Scholar
- 4.ASTM C 848-78 (Riappruved 1983), Standard Test Method for Young’s modulus, Shear modulus, and Poisson’s ratio for ceramic whitewares by resonance.Google Scholar
- 5.Day, P, and Locker, R, Decomposition behaviour of aluminium titanate solid solutions, Proc. Ceramics for Environmental Protection, 7-9 December 1988, Cologne (West Germany).Google Scholar
- 7.Demaestri, P.P, and Giachello, A, Characterization of β-A12TiO5 aged at 1000°C, Proc. World Ceramics Congress, 24–30 June 1990, Montecatini (Italy).Google Scholar