Fundamental Materials Dynamics of Protective Overlay Coatings for High Temperature Structural Materials

技术支持：该资助支持基础研究，探索涂层化学和微观结构对新型NiAl-Hf覆盖粘结涂层的机械性能和抗氧化性的影响。该涂料专为高温结构应用而设计。该研究依赖于新型微机械和分析技术的应用来表征多相溅射沉积覆盖涂层的微观结构和性能。技术动机是开发新型涂层，以提高针对高温结构应用的新兴工程结构的能力和耐久性。虽然该计划主要针对热障涂层系统的粘合涂层的开发，但相关应用包括硅基陶瓷的环境屏障涂层和高速切削工具的覆盖涂层。对微观结构改性（即，晶粒形态和沉淀物分布）将为更薄、更耐用的涂层的开发和应用开辟新的视野。非技术性：该项目通过培养研究生对科学和工程基础设施产生了积极影响。该项目的两名研究生涉及表面科学、物理化学、冶金和陶瓷工程、薄膜科学、材料加工、微观结构表征和材料选择等方面。学生受益于参与先进的研究在微机械，化学和多层材料的微观结构表征。他们使用最先进的分析工具。从大一和大二班本科生的整合在亚拉巴马和邻近HBCU的大学为这些学生提供了实际的实验室经验以上，超出了通常与他们的学术课程。此外，该项目与先进涂层技术的相关性为这项工作提供了强大的实践动力，同时也为相关学生提供了良好的职业选择。

TECHNICAL: This grant supports fundamental research that explores the influence of coating chemistry and microstructure on the mechanical properties and oxidation resistance of novel NiAl-Hf overlay bond coatings. The coatings are designed for use in high-temperature structural applications. The research relies on the application of novel micromechanical and analytical techniques to characterize the microstructures and properties of multiphase, sputter-deposited overlay coatings. The technological motivation is development of novel coatings that will increase the capability and durability of emerging engineering structures targeted for high-temperature structural applications. While this program is primarily directed towards the development of bond coatings for thermal barrier coating systems, related applications include environmental barrier coatings for silicon-based ceramics and overlay coatings for high speed cutting tools. A basic understanding of the changes in coating properties produced by microstructural modification (i.e., grain morphology and precipitate distribution) will open new horizons for the development and application of thinner, more durable coatings. NONTECHNICAL: This project has a positive impact on science and engineering infrastructure through the training of graduate students. The two graduate students in the project employ aspects of surface science, physical chemistry, metallurgical and ceramic engineering, thin film science, materials processing, microstructural characterization, and materials selection. The students benefit by being involved in advanced research in the micromechanical, chemical, and microstructural characterization of multilayered materials. They utilize state-of-the-art analytical tools. The integration of undergraduate students from the freshman and sophomore classes at the University of Alabama and from neighboring HBCU's provides those students with practical laboratory experiences above and beyond that normally associated with their academic coursework. In addition, the relevance of the project to advanced coating technologies provides a strong practical motivation for the work in addition to ensuring good career options for the students involved.