Microstructural Characterization and Thermal Properties of Aluminium Titanate/Spinel Ceramic Matrix Composites

Abstract

Spinel (MgAl2O4) ceramics possesses a high melting point, high hardness, a relatively low density, excellent transmittance, a high strength, a relatively low thermal expansion coecient, high thermal shock resistance and high chemical inertness. Aluminium titanate (Al2TiO5) exhibits extremely good thermal shock resistance and low thermal conductivity coupled with good chemical resistance in molten metals. In the present work, aluminium titanate/spinel ceramics composites with dierent percentages of Al2TiO5 were prepared using powder metallurgy techniques. The microstructural, mechanical and thermal properties were characterized using X-ray diraction, scanning electron microscopy, dierential scanning calorimetry, dilatometer and hardness. Thermal shock resistance behaviour under water quenching of the as-prepared ceramics was also evaluated. Results revealed that the addition of aluminium titanate to spinel matrix improves the properties of the aluminium titanate/spinel ceramics.

Experimental study of phase equilibria in the Al2O3–MgO–TiO2 system and thermodynamic assessment of the binary MgO–TiO2 system

“…The Al 2 O 3 –MgO–TiO 2 system obeys interesting properties important for industrial applications: MgAl 2 O 4 ‐based materials have a good combination of physical and chemical properties such as high refractoriness, high mechanical strength and high resistance to chemical attack, while the addition of Al 2 TiO 5 improves the thermal shock resistance of alumina‐rich magnesium aluminate spinel. As an understanding of the complex behavior of ceramics, the study of the MgO–TiO 2 and Al 2 O 3 –MgO–TiO 2 systems with considering their phase relations is recommended.…”

Thermal Properties and Microstructural Characterization of Aluminium Titanate (Al2TiO5) / La2O3 -Stabilized Zirconia (ZrO2) Ceramics

“…The monoclinic phase exists at the room temperature and the temperatures greater than 1170 °C it transforms to the tetragonal form. The tetragonal phase is constant at temperatures of 1170 -2370 o C, and the cubic phase occurs at over 2370 °C [1][2][3][4][5][6][7]. The transition from tetragonal form to monoclinic phase (about 9%) undergoes large volume change in microstructure which makes difficult to obtain stable sintered zirconia ceramic products.…”

The effects of silica addition on the structural, electrical and mechanical characteristics of MgAl2O4 spinel ceramic phase

“…Synthesizing and preparation of spinel MgAl 2 O 4 is known since long. A numerous techniques such as conventional solid-state-reaction, sol-gel, and spray drying and organic gel-assisted citrate complication were widely utilized [5].…”

“…The ionic radii of tetrahedral A-sites in the spinel structure (r A ) and B-octahedral (r B ) can be determined from the Eqs. (5,6), where r A is the tetrahedral A-sites radii, r B is octahedral B-sites radii and u is the oxygen parameter. The ideal u value is close to 0.375 (Å) in spinel, and r (O -2 ) is the ionic radii of oxygen.…”

“…The ideal u value is close to 0.375 (Å) in spinel, and r (O -2 ) is the ionic radii of oxygen. a =d hkl (h 2 +k 2 +l 2 ) 1/2 (4) r A = (u-1/4) a (3) 1/2 -r (O 2-) (5) r B = (5/8u) ar (O 2-) (6) where the R B and R A is ionic destines bond, and (h k l) are the miller indices [10]. A-and B-site radii, bond length and oxygen parameter as a function The qualitative results showed that the phases in calcined spinel specimen at temperatures 1450 o C consisting of only MgAl 2 O 4 spinel phase having crystallite size below 25 nm.…”