Direct measurements of fusion and phase transition enthalpies in lanthanum oxide
Direct measurements of fusion and phase transition enthalpies in lanthanum oxide
复制标题
直接测量氧化镧中的熔化和相变焓
DOI：
10.1557/jmr.2010.79
复制
发表时间：
2011
影响因子：
2.7
通讯作者：
A. Navrotsky
中科院分区：
文献类型：
--
作者：
S. Ushakov;A. Navrotsky
首次直接测定了氧化镧（La_2O_3）的高温相变焓和熔合焓。采用激光熔化法制备了3个样品，密封在钨坩埚中，并在熔化Al_2O_3校准的差热分析仪中加热。La_2O_3在2046±5℃时从A相到H相的转变焓为23±5 kJ/mol，在2114±5℃时从H相到X相的转变焓为17±5 kJ/mol。氧化镧在2301±10℃熔解，熔解焓为78±10 kJ/mol。
Enthalpies of high-temperature phase transitions and fusion in lanthanum oxide (La_2O_3) were directly measured for the first time. Three samples were prepared by laser melting, sealed in tungsten crucibles, and heated in a differential thermal analyzer calibrated by melting Al_2O_3. Transformation enthalpy of La_2O_3 from A to H phase is 23 ± 5 kJ/mol at 2046 ± 5 °C and from H to X phase is 17 ± 5 kJ/mol at 2114 ± 5 °C. Lanthanum oxide melts at 2301 ± 10 °C, with enthalpy of fusion of 78 ± 10 kJ/mol.