Synthesis and characterization of nanocrystalline Barium Strontium Titanate powder via sol-gel processing

Abstract

Barium Strontium Titanate (BST) solid solution is a strong candidate material for application in tunable ferroelectric devices. In this research, we have synthesized and characterized nanocrystalline BST (Ba 0.7 Sr 0.3 TiO 3 ) powder with average particle-diameter of 15 nm through a simple sol-gel process, using barium acetate, strontium acetate and titanium isopropoxide as the precursors. In this process, stoichiometric proportions of barium acetate and strontium acetate were dissolved in acetic acid followed by refluxing, and addition of titanium (IV) isopropoxide to form BST gel. The gel was analyzed using Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). The as-formed gel was dried at 200°C and then calcined in the temperature range of 400 to 800°C for crystallization. Phase evolution during calcination was studied using X-ray diffraction (XRD) technique. Particle size, morphology and the lattice fringes of the calcined powder were characterized by high-resolution transmission electron microscopy (HR-TEM). To study the effects of sintering on BST nanopowder, green ceramic specimens were prepared by uniaxial compaction and then sintered at 950-1,100°C under atmospheric conditions. Sintered specimens were analyzed for phase composition, grain size and geometric bulk density.

Characterization of metal (Fe, Co, Ni, Cu) and fluorine codoped barium strontium titanate thick-films for microwave applications

“…1. The TG curves of undoped as well as doped BST indicate that there are three apparent decreases in sample weight, which coincide with the decomposition behaviours of barium-titanium acetate gel precursors [17] and BST gel precursors [18][19][20] described in the literature. The first step begins at 100 • C and ends at 220 • C. This step can be explained with the vaporization of water and acetic acid which remained in the precursor after spraydrying.…”

Sinterability and dielectric properties of Ba0.55Sr0.4Ca0.05TiO3–CaTiSiO5–Mg2TiO4 composite ceramics

“…However, the high sintering temperature of approximately 1400 • C needs to be lowered for the application on the LTCC technology [11]. Although nanometer powders prepared by liquid-phase methods [12][13][14][15] and sintering agents such as B 2 O 3 [3], Si 2 O 3 [16], and Li 2 CO 3 [17,18] have been used to fabricate low-temperature sintering BST ceramics, reports on the low sintering BST-Mg 2 TiO 4 composite system are rare so far. As was reported [19], the dielectric constant and loss tangent of CaTiSiO 5 are 45 and 5 × 10 −4 measured at room temperature and 1 MHz, respectively.…”

Synthesis of BaTiO3 by soft chemistry routes

“…Soft chemistry routes are widely apply for producing stoichiometric BaTiO 3 nanopowders with narrow particles size distribution and low tendency of agglomeration. The uniform composition achieved by these methods due to finer scale mixing of barium and titanium cations implies lower temperature of ceramics obtaining [1][2][3][4][5]. Therefore, many efforts have been focused on the optimization of the BTO ceramics processing [6,7] in order to improve mainly their dielectric behavior.…”