POWRE: Electron Microscopy Studies of the Microstructure and Chemistry of Interfaces in Thermal Barrier Coating Systems

该项目研究了面漆/热生长氧化物(TGO)/键合层界面的微观结构、成分和键合方面，以了解和控制热障涂层的剥落问题。目标是开发一套材料和工艺建议，以生产具有更高可靠性和降低剥落倾向的TBC（热障涂层）系统。第二个目标是定制这种改进的TBC系统，以承受飞机涡轮应用中更高的工作温度。电子显微镜（TEM）将用于检查相存在于氧化铝作为一个功能的加工条件和热循环。目的是将TBC加工过程中氧化铝层中发生的任何相变与剥落相关联。微量的活性元素添加可以导致不同氧化物的形成，这将通过探测键合层的晶界和TGO/键合层界面来研究键合层化学的功能，以获得活性元素的偏析。高分辨率成像和电子能量损失光谱（EELS）的结合将被用于研究这种偏析问题。目的是利用EELS获得的键合信息来确定其他氧化物的存在对TGO/键合层界面强度的影响。这是在研究和教育领域妇女专业机会（POWRE）计划下提供的一项研究加强补助金。该研究将为飞机涡轮热障涂层提供相关的基础材料科学知识。该项目鼓励研究生直接参与与课堂活动相关的研究，从而将研究与教育结合起来。该项目由材料研究部和MPS OMA（多学科活动办公室）共同支持。* * *

This project investigates the microstructural, compositional, and bonding aspects of the topcoat/thermally grown oxide(TGO)/bondcoat interfaces to understand and control the spallation problem of thermal barrier coatings. The goal is to develop a set of materials and processing recommendations which will produce a TBC(thermal barrier coating) system with improved reliability and a reduced propensity for spallation. A secondary goal is to tailor this improved TBC system to withstand higher operating temperatures in aircraft turbine applications. Electron microscopy(TEM) will be used to examine the phases present in alumina as a function of processing conditions and thermal cycling. The objective is to correlate any phase transitions that occur in the alumina layer during TBC processing to spallation. Trace additions of reactive elements can lead to the formation of different oxides, and this will be investigated as a function of bondcoat chemistry by probing grain boundaries in the bondcoat layer and the TGO/ bondcoat interface for the segregation of reactive elements. A combination of high resolution imaging and electron energy loss spectroscopy (EELS) provided by an ultrasmall probe in a UHV STEM will be used to study this segregation issue. The goal is to use bonding information obtained from EELS to determine the effect of the presence of other oxides on the strength of the TGO/bondcoat interface.%%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The research will contribute basic materials science knowledge relevant to thermal barrier coatings used in aircraft turbines. The project encourages the integration of research and education through direct graduate student participation in research related to classroom activities. The project is co-supported by the Division of Materials Research, and the MPS OMA(Office of Multidisciplinary Activities). ***