【摘要】 采用XRD和Raman光谱研究了γ-Al2O3的高温相变。Raman结果表明,位于1 175,1 241 cm-1和1 370,1 400 cm-1的2组谱峰是杂质Fe3+和(或)Cr3+在θ-Al2O3和α-Al2O3环境中产生的荧光光谱,用这2组峰来指认θ-Al2O3和α-Al2O3物相比XRD更灵敏。因此,Raman技术能高灵敏地表征γ-Al2O3的高温相变过程。结果表明γ-Al2O3从800℃开始发生相变,γ-Al2O3同时向θ-Al2O3和α-Al2O3转变,随着温度的升高最终完全转变成α-Al2O3。相变温度与样品本身有关。更多还原

【Abstract】 The phase transformation of γ-Al₂O₃ at high temperature was characterized by XRD and Raman techniques.Raman results show that under the excitation at 632.8 nm,the Raman shift bands at 1 175 and 1 241 cm^-1 and the other two bands at 1 370 and 1 400 cm^-1 are attributed to the Cr³⁺ and（or） Fe³⁺ fluorescence bands in θ-Al₂O₃ and α-Al₂O₃ environments respectively.Compared with XRD measurements,it is more sensitive to use these two groups of Raman bands to estimate the phase formation and transformation of θ-Al₂O₃ and α-Al₂O₃.Therefore,Raman spectroscopy can deduce the high temperature phase transformation effectively.Experiments results show that γ-Al₂O₃ starts to transform to θ-Al₂O₃ and α-Al₂O₃ synchronously at 800 ℃,but the nature of the sample determines the final temperature of transforming to α-Al₂O₃.更多还原