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Structural changes caused by mechanical activation of SrTiO3 powders were investigated using a variety of methods. Average crystallite size continuously decreased with increased activation time to around 20 nm after 120 min activation, while mesopore volume and specific surface area increased accordingly. Higher activation times lead to increased agglomeration of nanoparticles to form agglomerates of around 2 μm in size, ultimately producing a relatively stable powder, which exhibits lower microstrain than powders activated for shorter periods of time. Raman spectroscopy shows that the behavior of TO2 and TO4 modes is consistent with a decrease in particle size, while behavior of the nonpolar TO3 mode is markedly different, indicating relaxation of the inversion symmetry in polycrystalline SrTiO3. UV-VIS spectra show that mechanical activation has negligible effect on SrTiO3, with a slight shift caused by TiO2 contamination due to presence of air. Other than this, the mechanical activation process preserves the chemical purity of the initial powder.

Structural changes caused by mechanical activation of SrTiO3 powders were investigated using a variety of methods. Average crystallite size continuously decreased with increased activation time to around 20 nm after 120 min activation, while mesopore volume and specific surface area increased accordingly. Higher activation times lead to increased agglomeration of nanoparticles to form agglomerates of around 2 μm in size, ultimately producing a relatively stable powder, which exhibits lower microstrain than powders activated for shorter periods of time. Raman spectroscopy shows that the behavior of TO2 and TO4 modes is consistent with a decrease in particle size, while behavior of the nonpolar TO3 mode is markedly different, indicating relaxation of the inversion symmetry in polycrystalline SrTiO3. UV-VIS spectra show that mechanical activation has negligible effect on SrTiO3, with a slight shift caused by TiO2 contamination due to presence of air. Other than this, the mechanical activation process preserves the chemical purity of the initial powder.

Ferroelectric barium strontium titanate (Ba0.77Sr0.23TiO3), BST, was prepared by solid-state reactions using as the starting compounds powder of barium carbonate (BaCO3), strontium carbonate (SrCO3) and titanium dioxide (TiO2–anatase). Non-activated mixtures and mixtures mechanically activated in a high-energy planetary ball mill (0, 5, 10, 20, 40, 80 and 120 min) were sintered at 1100, 1200, 1300 and 1400 °C for 2 h in air atmosphere. Defects and the effect of the beginning of the sintering process on the microstructure were investigated by scanning electron microscopy (SEM). Electrical measurements (loss tangent and resistivity as the function of frequency XC=f(log ν)) were performed for ceramics sintered at 1400 °C for 2 h. It has been found that mechanical activation can reduce the sintering temperature by around 100 °C, which leads to significant energy savings. Furthermore, activated for 80 min and sintered at 1400 °C for 2 h exhibit the largest density values and have about 36% lower dielectric loss at a frequency of 1 kHz and about 57% at a frequency of 10 kHz than the samples obtained from the initial non-activated powder sintered under the same conditions.