Nuclei-growth optimization for fine-grained BaTiO₃ by precision-controlled mechanical pretreatment of starting powder mixture

Abstract

By a solid-state process, well-crystallized BaTiO3 (BT) particles with their average grain size below 0.2 μm were obtained. Wet and dry mechanical pretreatment processes were combined to obtain fine particulate mixture comprising BaCO3 and TiO2 with the highest possible homogeneity without causing appreciable agglomeration. Degree of homogenization was quantitatively evaluated by different microscopic techniques, in an attempt to optimize nuclei-growth processes. Reaction processes were discussed on the basis of thermal analyses in conjunction with the particulate morphology. The granulometrical and crystallographical properties of the present particulate products are comparable with or even superior to commercially available high-valued products fabricated via a hydrothermal or sol-gel route.

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

“…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.…”

Polyethyleneimine surfactant effect on the formation of nano-sized BaTiO3 powder via a solid state reaction

“…1 shows DTA/TG curves of the BaCO 3 (PBT) and TiO 2 mixture. A broad endothermic peaks from around 570 • C to 1070 • C, corresponding to a multiple step weight loss in the same temperature range, can be ascribed to the decarboxylation of BaCO 3 [2]. In addition, there is a small endothermic peak around 800 • C, which is attributed to the phase transformation of BaCO 3 from the orthorhombic into the hexagonal phase [17].…”

“…However, a solid-state reaction occurring at higher temperatures easily leads to coarsening and agglomeration. Recently, a few researchers succeeded in preparing nano-sized BaTiO 3 powders using a solid state reaction below 1000 • C [1][2][3][4][5][6][7][8][9][10][11][12][13]. Therefore, the synthesis of nano-sized BaTiO 3 powder using a solid state reaction has becomes the research focus because of the lower cost, simpler process and higher productivity.…”

Synthesis of submicron BaTiO3 particles by modified solid-state reaction method

“…Milling treatment could be a method for deagglomeration of the BaTiO 3 powder obtained from solid-state reaction; however, a leach of barium ions into the aqueous suspension often occurs and results in stoichiometric problem [7]. Several chemical routes such as oxalate, sol-gel and hydrothermal methods for synthesizing fine and weakly agglomerated BaTiO 3 powder have been proposed; nevertheless, these methods are relatively more expensive than solid-state reaction and the particle sizes obtained are generally smaller than 100 nm [8][9][10][11][12][13]. Buscaglia et al have synthesized BaTiO 3 particles by mixing BaCO 3 (∼1 m) with peroxy-Ti aqueous solution and obtained BaTiO 3 pure-phase via a calcination treatment at a temperature as low as 700 • C [14,15].…”