| 氧离子导体La2Mo2O9中α→β相变非等温动力学的研究 |
| Non-isothermal Kinetics Analysis of α→β Transformation in the Oxide-Ion Conductor La2Mo2O9 |
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| 摘要: 以差热分析(differential thermal analysis, DTA)为手段研究了La2Mo2O9中α→β相变的非等温动力学。采用Flynn-Wall-Ozawa法计算了不同转化分数下的相变活化能E，并用Ozawa迭代法对E值进行了修正。应用Criado-Ortega法获得了α-La2Mo2O9→β-La2Mo2O9相变各温度区间的动力学机理函数，并用?atava-?esták法进行了验证。结果表明：La2Mo2O9中α→β相变的表观活化能与转化分数有关，说明该相变不属于一步简单反应。不同温度区间α→β相变的动力学机理函数不同，836~840 K、842~848 K和850~853 K的动力学机理函数G(x)可依次表示为：-ln(1-x)、[-ln(1-x)]2/3、[-ln(1-x)]3/4。 |
| 关键词: 钼酸镧 非等温动力学 热分析 |
| 基金项目: |
| Abstract: The non-isothermal kinetics of α→β transformation in La2Mo2O9 was investigated using the differential thermal analysis (DTA). The DTA curves were measured from the room temperature to 1 073 K at the heating rate of 10, 15, 20, 25 and 30 K·min-1 respectively. The Flynn-Wall-Ozawa (FWO) method was used to determine the apparent activation energies of α→β transformation at different conversion rates. Then the values of activation energy obtained were adjusted using Ozawa iterative equation. The most probable mechanism functions were suggested by means of the Criado-Ortega and ?atava-?esták methods. The analysis of the present data shows that the activation energy changes with the change of conversion rate. This result indicates that the α→β transformation in La2Mo2O9 is not a simple reaction but a complex multi-step involving several processes. The most probable mechanism functions are different in various ranges of temperature, which are -ln(1-x) for 836~840 K, [-ln(1-x)]2/3 for 842~848 K and [-ln(1-x)]3/4 for 850~853 K respectively. |
| Keywords: lanthanum molybdate non-isothermal kinetics thermal analysis |
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| 阮 北,闫柏军,张家芸.氧离子导体La2Mo2O9中α→β相变非等温动力学的研究[J].无机化学学报,2012,28(7):1417-1422. |
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