GOALI: Fundamental Investigation of the Synthesis, Characterization, and Performance of a NiAl Diffusion Coating Doped with a Reactive Element by Chemical Vapor Deposition

9801042 Lee热障涂层(TBC)由耐应变陶瓷层和金属粘结层组成，为金属合金提供氧化保护。在这些材料系统中观察到的主要失效模式是粘结层表面与其氧化膜之间的界面区域在暴露于氧化时逐渐断裂。在镍基高温合金渗铝形成的NiAl扩散层中加入一种或多种反应元素，如Hf或Zr，是改善粘结层表面结垢性能的有效途径之一。这笔赠款源于化学气相沉积(CVD)渗铝技术的最新制造进展。与传统的近批次渗铝和气相渗铝方法不同，开流CVD技术的动态特性提供了主动控制涂层基质中掺杂浓度和分布的前景。以前对块体合金和金属间化合物的研究表明，为了使有益的效果发挥作用，活性元素必须存在于一个良好控制的水平和分布在基质材料中。史蒂文斯理工学院与通用电气飞机发动机公司(GEAE)合作，正在探索与CVD兴奋剂概念相关的合成、表征和性能问题。这是在NSF-GOALI概念下完成的，这是通过大学和行业合作研究活动进行长期探索的理想选择。该研究项目有效地将史蒂文斯在进行动力学实验、涂层表征和数学建模方面的优势与GEAE作为具有独特表征和测试设施的领先飞机发动机制造商的专业知识结合在一起。材料研究部和MPS多学科活动办公室共同资助这笔赠款。扩展先进金属和陶瓷材料的表面功能一直是高温结构应用研究和开发的重要领域。目前，存在着通过表面涂层和改性方法来改善诸如镍基高温合金等传统结构材料的性能的强烈技术需求。***

9801042 Lee Thermal barrier coatings (TBCs) consist of a strain-tolerant ceramic layer and a metallic bond coat, which provides oxidation protection to metal alloys. The dominant failure mode observed in these material systems is the progressive fracture of the interface region between the bond coat surface and its oxide scale upon exposure to oxidation. One potent avenue for improving the scale adhesion at the bond coat surface is to incorporate one or more reactive elements, such as Hf or Zr, into a NiAl diffusion coating formed by aluminizing the surface of a Ni-based superalloy. This grant results from recent manufacturing advances in aluminizing by chemical vapor deposition (CVD). In contrast to the close-batch pack cementation and gas phase pack methods traditionally used for aluminizing, the dynamic nature of the open-flow CVD technique offers the promise of proactively controlling dopant concentration and distribution in the coating matrix. Previous studies with bulk alloys and intermetallics have shown that, in order for the beneficial effect to be operative, a reactive element must be present in a well-controlled level and distribution in the matrix material. Stevens Institute of Technology in collaboration with General Electric Aircraft Engines (GEAE) is exploring the synthesis, characterization, and performance issues associated with the CVD doping concept. This is accomplished under the NSF-GOALI concept, which is ideal for long-term exploration by collaborative university- industry research activities. This research project effectively integrates Stevens' strengths in conducting kinetic experiments, coating characterization, and mathematical modeling with GEAE's expertise as a leading aircraft engine manufacturer with unique characterization and test facilities. The Division of Materials Research and the MPS Office of Multidisciplinary Activities jointly fund this grant. %%% Extending the surface functionality of advanced metallic and ceramic materials has been a vital area of research and development for high temperature structural applications. Currently a strong technological need exists to improve the performance of "traditional" structural materials, such as Ni-based superalloys, via surface coating and modification approaches. ***