An investigation was made regarding the variation in internal friction and relative modulus with Ii5.3 La2.7Ba0.3 Ta2O12 compound by means of force vibration. Two apparent relaxation internal friction peaks were observed. By fitting the data with two Debye peaks, the activation energy and pre-exponential factor of the peaks are deduced as 1.1-1.2 eV and 10-18-10-21 s, respectively, which indicates occurrence of mutual interaction between the relaxation species. By fitting the data with the coupling model, the activation parameter of lithium ion diffusion in Ii5.3La2.7Ba0.3Ta2O12 compound is deduced as 0. 54-0. 57 eV 和 10-16 -10-15 s, close to the typical pre-exponential factor( 10-14-10-13 s) of the peaks from the point defect diffusion. Judging from the crystal structure of the Ii5.3La2.7Ba0.3Ta2O12 compound, the P1, and P2 peaks are suggested to be related with the lithium ionic diffusion between different octahedron or octahedron and tetrahedron.%采用低频内耗仪强迫振动方法测量了锂离子导体Li5.3 La2.7Ba0.3Ta2O12在升温过程中的内耗并结合晶体结构分析其形成机制.结果表明:在Li5.3 La2.7 Ba0.3Ta2O12中出现了两个明显的内耗峰,其弛豫元之间存在相互作用,由德拜模型拟合得到锂离子扩散的激活能和指前因子分别为1.1-1.2 eV和10 -18-10-21 s；利用耦合模型对其处理得到锂离子弛豫参数分别为0.54-0.57 eV和10-16-10-15s,后者和点缺陷扩散的指前因子的范围10-14-10 -3 s更为接近,可见耦合模型对Li53La2.7Ba0.3Ta2O12锂离子导体中锂离子扩散的描述更为恰当.结合晶体结构的特征分析可得,这两个内耗峰源自于锂离子在八面体和四面体之间扩散或者八面体和八面体之间扩散.
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