Influence of La Doping on the Apparent Activation Energy of α-Al2O3 during the Densification Process at Constant Heating-Rate

Feng Wang; Shaou Chen; Wei Quan Shao; Jian Jian Wang; Zhen Wang

doi:10.4028/www.scientific.net/AMR.709.23

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Influence of La Doping on the Apparent Activation Energy of α-Al₂O₃ during the Densification Process at Constant Heating-Rate

Abstract:

The apparent activation energy for densification is a characteristic quantity that elucidates the fundamental diffusion mechanisms during the sintering process. Based on the Arrhenius theory, the activation energy for densification of the pure and La doped α-Al₂O₃ at constant heating-rates sintering has been estimated. Sintering of α-Al₂O₃ and La doped powder has been executed by the way of a push rod type dilatometer. It was shown that the shrinkage and the relative density of the samples decreased with increasing heating rates. At the same sintering condition, the shrinkage of the pure α-Al₂O₃ was higher than that of the La doped. According to the calculation, it was found that the apparent activation energy had a single value and did not depend on the relative density for both samples. The apparent activation energy of the pure α-Al₂O₃ was 374.3kJ/mol, which was lower than that of La doped (966.5kJ/mol). So the densification process for α-Al₂O₃ was retarded due to La doping, which was consistent with experimental results of the shrinkage.