Characterisation of microstructure and hardness of perovskite-structured Ba_0.5Sr_0.5Co_0.8Fe_0.2O_{3 ∿δ} under different sintering conditions

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• 作者：Li Wang^a ; ^{li.wang-5@postgrad.manchester.ac.uk" class="auth_mail" title="E-mail the corresponding author} ; Rui Dou^b ; Mingwen Bai^a ; Yizhe Li^a ; David Hall^a ; Ying Chen^a ; ^{ying.chen-2@manchester.ac.uk" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Porosity ; Hardness ; BSCF ; Grain growth kinetics ; EBSD
• 刊名：Journal of the European Ceramic Society
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：36
• 期：7
• 页码：1659-1667
• 全文大小：3177 K

文摘

Microstructural evolution of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3 − δ (BSCF) has been investigated using commercial powders sintered at different conditions. All the samples, characterised by the porosity P and grain size D, are determined to be a single cubic phase. The grain growth kinetics is evaluated using Dⁿ = tK₀exp(−Q/RT). Grain boundary diffusion is the dominant controlling mechanism of densification and the Ba/Sr diffusion is the rate-controlling species. Additionally, the Vickers hardness (H_V) of BSCF is measured at ambient condition. The H_V is successfully described by an exponential function of porosity, H_V = H₀exp(−bP). The porosity is the dominant factor determining the hardness when it is over 0.06. Otherwise, the Vickers hardness shows a dependence on pore size. Compared with the strong dependence of hardness on porosity, no correlation between hardness and grain size or grain orientation has been found.