Study of safety science focused on nano-structure for hot section parts of advanced gas turbines

众所周知，残余应力影响热障涂层（TBCs）的退化。在这一年中，我们使用日本同步辐射研究所（JASRI）的同步辐射Spring-8评估了TBC厚度方向的残余应力。此外，还在上一财政年度的基础上开发了高灵敏度的无损评价技术。由于镍基高温合金基体和氧化钇稳定氧化锆（YSZ）顶层涂层之间的热膨胀系数不同，TBC系统产生了热应力。此外，由于长时间的操作，热生长的氧化物在顶涂层和粘结涂层之间的界面处形成并生长，然后热应力发展。可以通过使用常规X射线衍射（XRD）来评估TBC表面上的残余应力。然而，在这种情况下，可以获得仅关于TBC的表面的信息。因此，同步辐射被用于评价TBC的内部。在这项研究中，进行了加热到1000 ℃然后冷却到室温的热循环试验。结果表明，在1次循环后，TBC内部产生了80 MPa的残余压应力。此外，开发了一种新的无损检测（NDI）技术，用于评价TGO的厚度。通过使用该技术，我们定量地评估了TGO。因此，它可以通过反射系数和相位角定量评估TGO厚度。此外，为了提高检测的灵敏度，采用了波导传感器和高频（20 GHz）信号。结果，随着频率的增加，检测的分辨率提高。

It is well known that residual stress affects degradation of thermal barrier coatings (TBCs). In this year, we evaluated the residual stress of thickness direction of the TBC by using synchrotron radiation Spring-8 at Japan Synchrotron Radiation Research Institute (JASRI). Moreover, development of high sensitive nondestructive evaluation technique based on results of previous financial year was carried out.Due to different coefficient of thermal expansion between a Ni base superalloy substrate and an yttria stabilized zirconia (YSZ) top coating, thermal stress of the TBC system is induced. Furthermore, due to operation for a long period of time, a thermally grown oxide forms and grows at the interface between the top coating and the bond coating, and then the thermal stress makes progress. It is possible to evaluate the residual stress on the surface of the TBC by using conventional X-ray diffraction (XRD). In this case, however, it can be possible to obtain information about only surface of the TBC. Therefore, the synchrotron radiation was used for evaluation of inside of the TBC. In this study, thermal cycle test, which heats up to 1000 deg.0 and then cool down to room temperature, was carried out. As a result, after 1 cycle, compressive residual stress of 80 MPa acts on inside of the TBC.Furthermore, a new nondestructive inspection (NDI) technique by electro-magnetic wave was developed for evaluation of the thickness of the TGO. By using the technique, we evaluated the TGO quantitatively. As a result, it makes it possible to quantitatively evaluate the TGO thickness by coefficient of reflection and phase angle. Moreover, in order to improve the sensitivity of the detection, wave guide sensor and high frequency (20GHz) signal were used. As a result, resolution of the detection improved with increasing the frequency.