Standard enthalpy, entropy and Gibbs free energy of formation of ^«A^» type carbonate phosphocalcium hydroxyapatites

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• 作者：Sonia Jebri^a ; Ismail Khattech^b ; ^{ismail.khattech@fst.rnu.tn} ; Mohamed Jemal^b
• 关键词：Carbonate hydroxyapatites ; Isoperibol calorimeter ; Heat of solution ; Enthalpy of formation ; Entropy of formation ; Gibbs free energy of formation
• 刊名：The Journal of Chemical Thermodynamics
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：106
• 期：Complete
• 页码：84-94
• 全文大小：1635 K
• 卷排序：106

文摘

A-type carbonate hydroxyapatites with 0 ⩽ x ⩽ 1 were prepared and characterized by DRX, IR spectroscopy and CHN analysis. The heat of solution was measured in 9 wt% HNO3 using an isoperibol calorimeter. The standard enthalpy of formation was determined by thermochemical cycle. Gibbs free energy has been deduced by estimating standard entropy of formation. Carbonatation increases the stability till x = 0.6 mol.