CAREER: Coatings for High Temperature Alloys

小行星9624927 燃烧化学气相沉积（CVD）是一种新型的化学气相沉积方法。 由于CVD是在开放的气氛中进行的，因此它有可能成为一种新的具有成本效益的涂层工艺。 在这个CAREER计划中，氧化铝涂层被应用于原型镍基合金，以评估CVD涂层对合金氧化的改善。 通过使用含有各种浓度的活性元素掺杂剂的CVD应用涂层，研究了与活性元素效应相关的几个关键问题。 通过研究掺杂和未掺杂的氧化铝鳞片和随后的表征，解决了活性元素添加剂在抑制阳离子扩散氧化铝鳞片的有效性。 这种抑制的机制探讨了临界浓度效应，以确定的偏析/缺陷对假设的有效性。 未涂层和涂层合金的高温腐蚀降解的机制进行了探索，以显着地增加在这一领域的现有知识基础的目标。 这种类型的工作对于优化设计用于经受腐蚀性环境的部件的涂层系统至关重要。 例如，薄陶瓷涂层可用于提高散装材料的耐腐蚀性。涂层作为环境和基材之间的屏障，以保护基材免受侵蚀以及气体和液体腐蚀剂的影响。 ***

9624927 Hampikian Combustion chemical vapor deposition (CVD) is a novel approach to chemical vapor deposition. Because CVD is carried out in an open atmosphere, it has the potential to be a new cost-effective coating process. In this CAREER program coatings of alumina are applied to prototype nickel- base alloys to assess improvements in oxidation imparted to the alloys by the CVD coatings. Several key issues related to reactive element effects are examined through use of CVD applied coatings containing various concentrations of reactive element dopants. The effectiveness of reactive element additions in suppressing cationic diffusion in alumina scales is addressed through study of doped and undoped alumina scales and subsequent characterization. The mechanism of such suppression is explored for a critical concentration effect to ascertain the validity of the segregant/defect pair postulate. The mechanism of degradation of the uncoated and coated alloys to high temperature corrosion is explored with the goal of adding significantly to the current knowledge base in this area. %%% Work of this type is vital for optimum design of coating systems for parts experiencing aggressive environments. For example thin ceramic coatings can be used to improve the corrosion resistance of bulk materials. The coatings act as barriers between the environment and the substrate to protect the substrate from erosion and gaseous and liquid corrodants. ***