## 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 (${\mathrm{Al}}_{2}{\mathrm{TiO}}_{5}$) 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 ${\mathrm{Al}}_{2}{\mathrm{TiO}}_{5}$ tends to decompose into ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ and ${\mathrm{TiO}}_{2}$ at temperatures ranging from 800 to 1300 $°$C. The addition of additives such as ${\mathrm{SiO}}_{2}$, ${\mathrm{ZrO}}_{2}$, mullite and ${\mathrm{ZrTiO}}_{4}$ restrict the thermal decomposition by limiting the grain growth.
The objective of the present work is to obtain ${\mathrm{Al}}_{2}{\mathrm{TiO}}_{5}$ ceramic materials stabilized with different zircon proportions, and study their sintering behavior and flexural strength.
For this, equimolar mixtures of ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ and ${\mathrm{TiO}}_{2}$ powders carried out; three different ${\mathrm{ZrSiO}}_{4}$ 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 ${\mathrm{Al}}_{2}{\mathrm{TiO}}_{5}$ phase. This was accompanied by ${\mathrm{ZrTiO}}_{4}$ and mullite as secondary phases.
An interlocking multiphase microstructure was determined. The developed grains size range was between 2 and 10 $𝝁$m. The presence of the typical micro-cracks was also described.
The sintering grade was enhanced by the presence of the $\mathrm{Zr}S{\mathrm{iO}}_{4}$. 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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