Synthesis of TaAlO4 compound and Al2O3–TaAlO4 composite ceramic by mechanical alloying and their sintering

• Published in: Ceramics international Vol. 41; no. 2; pp. 2260 - 2265
• Main Authors: Gondim, Meryane Fátima, Maestrelli, Sylma Carvalho, Ramos, Erika Coaglia Trindade, Rodrigues, José Augusto Jorge, Ramos, Alfeu Saraiva
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2015
• Subjects: B. Composite; Catalysts; D. Transition metal oxides; Powder processing solid state; D. Transition metal oxides; Powder processing solid state; Catalysts; B. Composite
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2014.10.029

This work discusses on the synthesis of TaAlO4 compound and Al2O3–TaAlO4 composite ceramic by mechanical alloying and subsequent sintering from the Al2O3–50mol%Ta2O5 and Al2O3–5mol%Ta2O5 powder mixtures, respectively. The samples were milled, compacted and sintered at 1200°C for 240min in order to obtain the equilibrium phases. The as-milled powders and sintered samples were characterized by X-ray diffraction, and BET analysis, He-picnometry, and DSC/TG analyses. Only peaks of α-Al2O3 and Ta2O5 were identified in XRD patterns of as-milled Al2O3–5mol%Ta2O5 and Al2O3–50mol%Ta2O5 powders. Results have indicated that Al ions were preferentially dissolved into the Ta2O5 lattice in order to form metastable structures. The average density of the Al2O3–5mol%Ta2O5 and Al2O3–50mol%Ta2O5 powder particles was reduced during ball milling while that their surface areas were continuously increased during ball milling, respectively. For the Al2O3–50mol%Ta2O5 powder mixture, the surface area was reduced during the initial milling time. After sintering at 1200°C for 240min, the TaAlO4 compound and Al2O3–TaAlO4 composite were formed from the mechanically alloyed Al2O3–5mol%Ta2O5 and Al2O3–50mol%Ta2O5 samples, respectively.