The kinetics of the heterogeneous solid state reaction between Al₂O₃ and Y₂O₃ is investigated by using thin film techniques. Y₂O₃ films are grown by means of pulsed laser deposition (PLD) on single crystalline alumina substrates with a (0001) orientation. The solid state reactions are performed at a temperature of 1400 °C (1673 K). The cross sections of the reacted samples were investigated by means of SEM and XRD and exhibit a sequence of three product layers, Y₃Al₅O₁₂ (YAG), YAlO₃ (YAP) and Y₄Al₂O₉ (YAM). The simultaneous growth of the product layers is controlled by a diffusional kinetics and the thickness increases are coupled to each other. According to Wagner and Schmalzried, one has to distinguish between rate constants of the first kind (“practical” Tammann constant), in the case of simultanous and coupled growth of multiple product phases, and rate constants of the second kind (“true” Tammann constant), in the case of the uncoupled and only growth of one product phase in equilibrium with the adjacent phases. The growth kinetics for a solid reaction forming three product phases (layer) is analysed in detail using linear transport theory. For the formation of YAG, YAP and YAM the rate constants of the second kind are determined from the experimental data and those of the first kind are calculated and compared to the available literature data. Based on these considerations, a detailed overview about the phase formation kinetics in the temperature range of 1200–1400 °C can be given for the first time. The (Nernst-Planck coupled) cation conductivities are calculated.

使用薄膜技术研究了Al ₂ O ₃和Y ₂ O ₃之间的多相固态反应动力学。Y ₂ O ₃膜通过脉冲激光沉积（PLD）在具有（0001）取向的单晶氧化铝基板上生长。固态反应在 1400 °C (1673 K) 的温度下进行。反应样品的横截面通过 SEM 和 XRD 进行研究，并显示出三个产物层的序列，Y ₃ Al ₅ O ₁₂ (YAG)、YAlO ₃ (YAP) 和 Y ₄ Al ₂ O ₉（芋头）。产品层的同时生长受扩散动力学控制，厚度增加相互耦合。根据 Wagner 和 Schmalzried 的说法，在多个产品相同时和耦合生长的情况下，必须区分第一类速率常数（“实际”泰曼常数）和第二类速率常数（“真实”泰曼常数）常数），在一个产品相与相邻相平衡的非耦合且仅生长的情况下。使用线性传输理论详细分析了形成三个产物相（层）的固体反应的生长动力学。对于 YAG 的形成，YAP 和 YAM 第二类的速率常数是根据实验数据确定的，第一类的速率常数是计算出来的，并与可用的文献数据进行比较。基于这些考虑，可以首次详细概述 1200-1400°C 温度范围内的相形成动力学。计算（Nernst-Planck 耦合）阳离子电导率。