Influence of Sr/Ti Stoichiometry on the Densification Behavior of Strontium Titanate

Abstract

In order to control the preparation of strontium titanate with a well‐defined Sr/Ti stoichiometry produced by the mixed oxide route, dilatometric experiments have been conducted for compositions with Sr/Ti ratios ranging from 0.996 to 1.005. A significant change in sintering behavior has been detected going from a titania rich to a strontia rich composition. Combining observations of the microstructural evolution during different stages of sintering with results on defect chemistry from the literature makes an assessment of the basic mechanisms of sintering possible. The influence of zirconia abrasion from milling balls has been identified to be equal to a titania excess of the same amount. By means of dilatometric measurements it is possible to evaluate the A/B ratio with accuracy higher than 0.2 mol% from the shrinkage curves, providing a highly sensitive tool for the analysis of the stoichiometry in SrTiO3.

Microstructural and electrical properties of Y0.07Sr0.93-x TiO3-δ perovskite ceramics

“…It was found that ASR LF +HF for both YS98TO and YS88TO samples is comparable (around 350 Ω cm). Thus, the influence of Sr nonstoichiometry can not be identified by the impedance spectroscopy measurements of donordoped SrTiO 3 . That leads to a conclusion that a relationship between microstructure of Y-doped SrTiO 3 and its electrical properties cannot be seen on impedance spectra.…”

“…One of the most widely used representatives of perovskite materials is strontium titanate (SrTiO 3 ). It has been reported in the literature that it is one of the most promising candidates for anode and cathode materials for Solid Oxide Fuel Cells, because of catalytic and conductivity performance [3,20]. However, in a pure form strontium titanate is a dielectric material, so it requires some modifications.…”

“…Moreover, the electrical and structural properties of SrTiO 3 strongly depend on its defects concentration. There are many scientific groups that investigate the influence of defect chemistry or Sr/Ti stoichiometry on these properties [3,8]. All equations presented below are written using a Kroger-Vink no- In Fig.…”

“…For example Blennow et al [8] showed that electronic conductivity of SrTiO 3 is associated with concentration of reduced Ti 4+ ions [reaction (2)]. The group of Baurer et al [3] investigated nonstoichiometric strontium titanate and reported that an excess of TiO 2 in the structure results in a formation of strontium and oxygen vacancies, even in oxygen atmosphere, according to Eq. …”

“…Therefore, much effort needs to be made in order to improve the properties of these structures [3]. One of the most widely used representatives of perovskite materials is strontium titanate (SrTiO 3 ).…”