Nonisothermal reaction kinetics and preparation of ferroelectric strontium bismuth niobate with a layered perovskite structure
Journal
Journal of Materials Research
Journal Volume
19
Journal Issue
10
Pages
2956-2963
Date Issued
2004
Author(s)
Abstract
Ferroelectric layered perovskite SrBi 2 Nb 2 O 9 has been successfully prepared through a new process using BiNbO 4 as a precursor. The SrBi 2 Nb 2 O 9 formation mechanism was investigated using a nonisothermal analysis method at constant heating rates. The weight loss recorded in thermal analysis under different heating rates was analogized to the reaction conversion. A combination of the differential and integral methods was introduced to solve the reaction mechanisms. Analysis using the differential method revealed that two kinds of diffusion-controlled models have higher linear correlation coefficients than other models. Based on the integral method principle, a new integral equation combining the Arrhenius equation and the Lobatto approximation was derived in this study. The established equation significantly simplified the conventional calculation process and improved the accuracy for predicting the reaction models. Analysis using the integral method corroborated that the SrBi 2 Nb 2 O 9 formation mechanism is governed by Jander's diffusion controlled model, and the activation energy was calculated to be 192.1 kJ/mol. The proposed methods and the derived equations can be further applied to other solid-state-reaction systems to elucidate their reaction kinetics and estimate the related kinetic parameters. ? 2004 Materials Research Society.
Type
journal article