Effects of ultrasonication and conventional mechanical homogenization processes on the structures and dielectric properties of BaTiO3 ceramics

Abstract

The effects of the homogenization process on the structures and dielectric properties of pure and Nb-doped BaTiO ceramics have been investigated using an ultrasonic homogenization and conventional mechanical methods. The reagents were homogenized using an ultrasonic processor with high-intensity ultrasonic waves and using a compact mixer-shaker. The components and crystal types of the powders were determined by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses. The complex permittivity (ε, ε″) and AC conductivity (σ') of the samples were analyzed in a wide frequency range of 20Hz to 2MHz at room temperature. The structures and dielectric properties of pure and Nb-doped BaTiO ceramics strongly depend on the homogenization process in a solid-state reaction method. Using an ultrasonic processor with high-intensity ultrasonic waves based on acoustic cavitation phenomena can make a significant improvement in producing high-purity BaTiO ceramics without carbonate impurities with a small dielectric loss.

Sonochemical activation in aqueous medium for solid-state synthesis of BaTiO3 powders

“…It is known that the size reduction owing to the ultrasonication can be attributed to mechanical fragmentation and chemical dissolution [24] , [33] , [34] , [35] , [37] . To verify the effect of pH on the dissolution of BaCO 3 , ICP measurements for the supernatant of 600 W ultrasonicated medium were performed.…”

“…Because of its high calcination temperature (∼1200 °C), solid-state reaction can provide highly dense BaTiO 3 powders, which is desirable in terms of reliability. Furthermore, it has been reported that submicron-sized BaTiO 3 powders can be successfully prepared via the solid-state reaction through appropriate pre-treatments of the raw materials, such as high-energy ball-milling and mechanochemical [29] , [30] , [31] , [32] and sonochemical activation [33] , [34] , [35] . These pre-treatments result in downsizing and uniform mixing of the raw materials, thereby facilitating the synthesis of BaTiO 3 powders through reaction (1).…”

Dielectric Characteristics of BaTiO3 Solid Solution Substituted with Nb5+, Ta5+, Bi3+, and Sb3+ Ions

“…γ is derived by fitting the modified Curie-Weiss law. For BT-Sb3, γ exhibits a slight decrease inversely proportional to the rise in heat treatment temperature [9][10][11][12]. As for the characteristics of BT-Sb3, EDS/FESEM observations in Fig.…”

Methods to Improve the Quality of Ceramic Products

“…In addition, to improve the technological properties and obtain higher-quality products, sumping is used -curing for a certain time and under certain conditions in order to destroy the natural structure, which leads to disintegration of the aggregated particles into elementary grains, an increase in the specific surface and a deepening of the swelling processes, an increase in the number of bound water, an increase in the plasticity and coherence of clay, an improvement in the molding and drying properties [1,2], the leaching of harmful impurities of soluble salts (su chlorites and chlorides) and others. However, in order to save money, many enterprises prefer to work "from the wheels".…”

“…In the study of the South Ural State University (Chelyabinsk), the following methods are used to improve the physicomechanical characteristics: mechanical activation, ultrasound and electromagnetic impulses [5], which favorably affects the rheological properties of clay suspensions. Russian [6][7][8][9][10] and foreign scientists [11][12][13][14] dealt with mechanical activation in ceramic systems. A number of works are devoted to questions of possible ways of modifying ceramic masses [1,4,[15][16][17], including using silicon carbide [5][6].…”