Role of Grain Structure and Grain Boundary Diffusion in Thin Film Reactions

9308651 Barmak这个项目研究了不同厚度和微结构的Nb-Al多晶薄膜中的晶界扩散和晶格结构。用量热法和透射电子显微镜研究了Nb3Al的形成动力学。根据形状、生长速率和形核密度的测量，将对Nb3Al形成的模型进行修改。成核点将与反应物层的微观结构特征相联系。分析电子显微镜将直接测量Nb3-XAl相的组成。随着Nb3Al层总界面积的增加，Nb3-xAl相的Al浓度增加，应为晶界扩散在反应中所起的作用提供直接证据。这项研究与微电子和磁性薄膜工业中使用的薄膜器件有关。***

9308651 Barmak This project examines grain structure and grain boundary diffusion in thin film niobium aluminide polycrystalline films of different thicknesses and microstructures. The kinetics of Nb3Al formation are studied with calorimetry and transmission electron microscopy. A model for the Nb3Al formation will be modified based on the measurements of shape, growth rate, and nucleation density. Nucleation sites will be linked to microstructural features of the reactant layers. Direct measurements of the composition of Nb3-xAl phase will be made by analytical electron microscopy. An increase in the Al concentration of the Nb3-xAl phase with an increase in the total boundary area of the Nb3Al layer should provide direct evidence for the role of grain boundary diffusion in the reaction. %%% This research has relevance to thin film devices used in the microelectronic and magnetic thin film industries. ***