An improvement in fracture toughness and strength is observed in carbon atmosphere sintered alumina on reheating the sintered samples in air at 1200°C. SEM photographs show the presence of secondary precipitate particles at grain boundaries of the sintered samples, which disappear after reheating in air. Infrared spectroscopy indicates that the C-O bond intensity increases on reheating in air. An AES/XPS study reveals that carbon enters the alumina lattice on reheating. These results lead to the conclusion that the enhanced fracture toughness and strength are related to the dissolution of precipitates and consequent dissolution of carbon in alumina lattice.
Volume 43, 2020
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