Oxidation resistance, residual strength, and microstructural evolution in Al2O3-MgO?C refractory composites with YAG nanopowder

The decisive role of nanostructured yttrium aluminium garnet (YAG;Y3Al5O12) powder addition on oxidation resistance, residual strength and microstructural evolution were studied in Al2O3-MgO?C refractory composites. Oxidation index and rate constant calculations indicated that the oxidation resistance was almost 70 % improved for the nano-YAG containing refractories oxidized in air at 1600 ?C. Residual compressive strength (Rc) estimations showed that there was nearly 75 % strength retained in these oxidized refractories fortified with nanoYAG. Residual bending strength (Rb) estimations based on cyclic thermal shock, exhibited that there was almost 70 % thermal shock resistance enhancement in refractories reinforced with nano-YAG, showed a good agreement between Rb and Rc values. These beneficial properties were attributed to the formation of a well-sintered framework of YAG/Spinel bonding grains throughout the dense oxidized layer microstructure of these new class of refractories. The concept of interfacial toughening and implications of these results to practical applications are discussed.

Automated summary

This study investigated the role of nanostructured YAG powder in Al2O3-MgO?C refractory composites, and found that the addition of nano-YAG significantly improved oxidation resistance, residual strength, and thermal shock resistance in the materials. This improvement was mainly attributed to the well-sintered framework of YAG/Spinel bonding grains formed in the dense oxidized layer microstructure of the refractories.