Sintering of Al₂O₃-TiO₂ Mixtures Obtained by High-Energy Ball Milling

Abstract:

In this work, the preparation of Al₂O₃-TiO₂ ceramics by high-energy ball milling varying the molar fraction in 1:1 and 3:1 was investigated. The powder mixtures were processed in a planetary mill at 250rpm and a ball-to-powder weight ratio of 5:1, for 120min. Compacts were obtained by cold pressing at 100MPa. These specimens were heated at 1000^◦C for 30min to promote the water evaporation, and subsequently sintered at 1500^◦C for 240min. Samples were characterized by relative density and X-ray diffraction. Hardness and fracture toughness were determined by Vickers Indentation Method. The crystallite sizes were lower than 420 and 560Å in Al₂O₃-TiO₂ and 3Al₂O₃-TiO₂ powders, respectively. After sintering, XRD analysis indicates Al₂TiO₅ and Al₂O₃/Al₂TiO₅ as major crystalline phases for Al₂O₃-TiO₂ and 3Al₂O₃-TiO₂ compositions, respectively. The relative density of the Al₂O₃-TiO₂ ceramics was higher than 90% in both compositions. However, hardness and fracture toughness results of 10.7GPa or 10.5GPa and 3.2MPa.m^1/2 or 2.6MPa.m^1/2 for Al₂O₃-TiO₂ and 3Al₂O₃-TiO₂ mixtures respectively, indicates that microstructure duplex composed by Al₂O₃ and Al₂TiO₅ grains lead to improvement of toughness of these ceramics.

• Periodical: Advances in Science and Technology (Volume 87)
• Pages: 157-161
• DOI: https://doi.org/10.4028/www.scientific.net/AST.87.157
• Online since: October 2014
• Authors: Alfeu Saraiva Ramos, Marisa Aparecida de Souza, Roberto de Oliveira Magnago*, Claudinei dos Santos, Camila Aparecida Araujo da Silva, Bianca de Almeida Fortes
• Keywords: Al₂O₃-TiO₂, Biomaterial, High-Energy Ball Milling, Sintering

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