Sintering and flexural strength of zircon (ZrSiO4) stabilized aluminum titanate (Al2TiO5) ceramics

Reference Presenter Authors
(Institution)
Abstract
09-039 María Agustina Violini Violini, M.A.(Centro de tecnología de recursos minerales y cerámica); Conconi, M.S.(Centro de tecnología de recursos minerales y cerámica); Suárez, G.(Centro de tecnología de recursos minerales y cerámica); Rendtorff, N.M.(Centro de tecnología de recursos minerales y cerámica); 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.
Pure Al2TiO5 tends to decompose into Al2O3 and TiO2 at temperatures ranging from 800 to 1300 °C. The addition of additives such as SiO2, ZrO2, mullite and ZrTiO4 restrict the thermal decomposition by limiting the grain growth.
The objective of the present work is to obtain Al2TiO5 ceramic materials stabilized with different zircon proportions, and study their sintering behavior and flexural strength.
For this, equimolar mixtures of Al2O3 and TiO2 powders carried out; three different ZrSiO4 proportions were studied (5, 15 and 30 % wt). Samples were pressed and sintered up to 1500 °C, with 2 h dwelling. The materials characterization included textural properties, mechanical properties and resulting crystalline phases. As well the microstructure (SEM) and thermal expansion behavior were studied.
The zircon addition stabilized the Al2TiO5 phase. This was accompanied by ZrTiO4 and mullite as secondary phases.
An interlocking multiphase microstructure was determined. The developed grains size range was between 2 and 10 𝝁m. The presence of the typical micro-cracks was also described.
The sintering grade was enhanced by the presence of the ZrSiO4. This was observed by the microstructural analysis and the porosity decrease; the achieved porosity was below 9.4 %. An almost null thermal expansion behavior was evaluated for the studied materials below 1000 °C.
Finally the flexural strength was evaluated. This is proportional to the sintering grade and the initial zircon addition; 48.7 MPa was achieved.
The obtained results encourage the use of this family of materials in structural applications subjected to severe thermomechanical conditions.
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