LAUSR

Abstract This study reports a simple method for the preparation of bulk amorphous materials by rapid solidification of their crystalline powders. Bulk amorphous Al 2 O 3 -YSZ materials have been successfully prepared by atmospheric plasma spraying (APS) using Al 2 O 3 -YSZ mixed crystalline powders near eutectic composition. Nano-crystalline Al 2 O 3 -YSZ materials with homogeneous nanostructure were achieved by heat treating bulk amorphous Al 2 O 3 -YSZ materials at 1050 °C. When annealing temperature was above 1250 °C, the lotus leaf structure was formed because of connection between large numbers of Al 2 O 3 nano-grains due to sintering. Therefore, it can be concluded that annealing temperature of amorphous Al 2 O 3 -YSZ materials need to be controlled between T c (onset crystallization temperature) and 1250 °C avoiding large area of sintering to achieve homogeneous nanocrystalline ceramics.