Processing of submicrometric CaTi0.8Fe0.2O3-delta ceramics by mechanical activation

作者：Fuentes R O^*; Chinarro E; Figueiredo F M; Soares R; Marques F M B; Frade J R

来源：Journal of Materials Science, 2006, 41(22): 7393-7400.

DOI：10.1007/s10853-006-0812-2

Effects of mechanical activation of precursors in order to obtain CaTi0.8Fe0.2O3-delta are reported. Mixtures of CaCO3, TiO2 and Fe2O3 were dry-grinded in Teflon or zirconia containers using planetary ball-mills at different rotations (200, 300 and 500 rpm) and for various periods of time. The perovskite is not formed just by milling and a subsequent heat treatment at 800-1,000 degrees C was necessary. This still represents a significant advantage over the classical ceramic route as a result of the improved reaction kinetics due to the smaller grain size (< 100 nm) of the activated powders and a modification of the thermodynamic initial state. Dense ceramic samples showing a bimodal submicrometric grain-size distribution (100-200 and 250-500 nm) were obtained after sintering the activated powders at 1,150 degrees C TEM revealed homogeneous samples, free from inhomogeneities such as core-shell grains typically observed in ceramics obtained from non-activated precursors sintered at 1,320-1,350 degrees C.

• 出版日期2006-11