Autores UPV
Inocente Jordana Mariot,
Wermuth Tiago Bender,
de Oliveira Antonio Pedro Novaes,
Borrell Tomás María Amparo,
Moreno Rodrigo,
Arcaro Sabrina,
Montedo Oscar Rubem Klegues
Abstract
In this study, we investigated the effect of aluminium niobate (AlNbO4) nanoparticles on the sintering behaviour, microstructure, and mechanical properties of alumina. Aluminium niobate nanoparticles (9-24 nm) were successfully synthesised using a colloidal process based on heterocoagulation followed by a solid-state reaction at 1100 degrees C. Alumina-based composites containing 5 vol% AlNbO4 were prepared via slip casting and conventional sintering. Results showed that AlNbO4 nanoparticles significantly reduced the sintering temperature of alumina by up to 300 degrees C, suppressed grain growth, and changed the fracture mechanism from transgranular to intergranular, resulting in increased energy absorption and delayed crack propagation. The samples sintered at 1300 degrees C for 60 min showed a densification of 95.2 %, with an average grain size of 0.7 f 0.4 mu m. This reduced grain size and change in the fracture mode contributed to an increase in the fracture toughness (KIC) from 3.2 f 0.3 (pure alumina) to 5.3 f 0.5 (sample 5NB.14) MPa & sdot;m0.5. Results showed that the alumina-based composites containing 5 vol% AlNbO4 nanoparticles exhibited superior mechanical properties, particularly in terms of fracture toughness, as compared to the composites prepared via conventional approaches.
