Thermodynamic calculations of t to m martenstic transformation of ZrO₂-CaO binary system

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• 作者：Jing Li^a ; ^b ; ^c ; ^d ; Jinhui Peng^a ; ^b ; ^c ; ^d ; ^{jhpeng@kmust.edu.cn} ; Shenghui Guo^a ; ^b ; ^c ; ^d ; Wenwen Qv^a ; ^b ; ^c ; ^d ; Wei Li^a ; ^b ; ^c ; ^d ; Libo Zhang^a ; ^b ; ^c ; ^d ; Guo Chen^a ; ^b ; ^c ; ^d
• 关键词：D. ZrO2 ; Thermodynamics ; Martensitic transformation ; The Gibbs free energy change ; CaO
• 刊名：Ceramics International
• 出版年：2012
• 期刊代码：13_02728842
• 类别：ms
• 出版时间：May, 2012
• 卷：38
• 期：4
• 页码：2743-2747
• 文件大小：257 K

摘要

The phase transformation of different polymorphs in zirconia is very important for the processing and mechanical properties of zirconia ceramics. This paper adopts thermodynamic model which is suitable for ceramic system to calculate the Gibbs free energy change of tetragonal and monoclinic phases in ZrO₂-CaO binary system. The difference of the Gibbs free energy between tetragonal and monoclinic phases in ZrO₂-CaO as a function of composition and temperature, namely t 鈫?#xA0;m phase transformation driving force, is thermodynamically calculated from the binary systems. Furthermore, in 8.0 mol%CaO-ZrO₂, the equilibrium temperature between tetragonal and monoclinic phases, T₀, was obtained as 1270.3 K, and martensitic transformation starting temperature (M_s) for t 鈫?#xA0;m transformation of this ceramic with a mean grain size of 2.0 mm was calculated as 805.9 K, which is good agreement with experiment one of 793 K with 12.9 K residual.