Lowering the synthesis temperature of high-purity BaTiO3 powders by modifications in the processing conditions

Synthesis of fine Ca-doped BaTiO3 powders by solid-state reaction method—Part I: Mechanical activation of starting materials

“…The effect of BaCO 3 milling on decreasing the reaction temperature was relatively smaller than that of fine anatase TiO 2 , due to the decomposition temperature differences among the three types of powder at this temperature range. The endothermic DTA peak near 640°C (peak a) was from the decomposition of BaCO 3 while that of near 840°C (peak b) was from the BaCO 3 phase transition from γ to β phase [13]. Since most of the BaCO 3 phase in A-powder was decomposed near 640°C, the endothermic peak of this powder was large in this region while the peak due to the γ→β phase transition was insignificant compared to that of other powders.…”

“…Even though all three powders contained CaCO 3 , most of the TG/DTA results were due to the effects of BaCO 3 and TiO 2 because the amount of CaCO 3 was very small. The weight loss between 600 and 900°C corresponded to the BaCO 3 decomposition [13]. A-powder had a lower decomposition temperature than R-and N-powders, due to the effects of fine, anatase-rich TiO 2 phase and previous milling of BaCO 3 .…”

“…A-powder had a lower decomposition temperature than R-and N-powders, due to the effects of fine, anatase-rich TiO 2 phase and previous milling of BaCO 3 . It has been reported that TiO 2 particles act as a catalyst for BaCO 3 decomposition [13,15], and that the density of anatase phase is lower (3.90 g/cm 3 ) than that of rutile one (4.23 g/cm 3 ) [16]. These facts suggest that the fine anatase TiO 2 is more effective than the coarse rutile phase in decreasing the reaction temperature due to its large surface area and loose structure.…”

“…This method tends to produce a significant amount of agglomeration, poor chemical homogeneity and coarse particle size due to the heat treatment at high temperature [3]. With the help of recently available advanced milling facilities and very fine starting materials, however, a few researchers have synthesized 200 nm-sized BaTiO 3 by this method [9][10][11][12][13][14]. Since the solid-state reaction occurs at the contact points of dissimilar materials, highly homogenized fine starting materials are very important for decreasing the reaction temperature and synthesizing fine particles.…”

Investigation of physicochemical transformation at mechanochemical, hydrothermal and microwave treatment of barium titanyloxalate

“…On the other hand, various types of apparatus are used in treatment. It should be noted that most of the available investigations concern MChA of either reaction mixture [11][12][13][14][15][16][17][18][19] or its components [20,21]. Such an approach allows to reduce annealing temperature from 1000-1100 • C to 600-700 • C at which interaction of reagents and BMT formation begins.…”