Badea Teodor-Adrian, Condruz Mihaela-Raluca, Paraschiv Alexandru
Romanian Research and Development Institute for Gas Turbines COMOTI, 220D Iuliu Maniu Av., 061126 Bucharest, Romania.
Materials Science and Engineering Faculty, University Politehnica of Bucharest, 060042 Bucharest, Romania.
Materials (Basel). 2023 Jul 27;16(15):5294. doi: 10.3390/ma16155294.
This paper focused on studying the performance of a nanostructured thermal barrier coating (TBC) system deposited by APS, which had a bond coat with inter-lamellar porosities that resulted during the manufacturing process. The higher porosity level of the bond coat was studied as a possible way to keep the thickness of the TGO under control, as it is distributed on a higher surface, thereby reducing the chance of top-coat (TC) spallation during long-term oxidation and high-temperature thermal shock. The TBC system consisted of nanostructured yttria partially stabilized zirconia (YSZ) as a top coat and a conventional NiCrAlY bond coat. Inter-lamellar porosities ensured the development of a TGO distributed on a higher surface without affecting the overall coating performance. Based on long-term isothermal oxidation tests performed at 1150 °C, the inter-lamellar pores do not affect the high resistance of nanostructured TBCs in case of long-term iso-thermal oxidation at 1150 °C. The ceramic layer withstands the high-temperature exposure for 800 h of maintaining without showing major exfoliation. Fine cracks were discovered in the ceramic coating after 400 h of isothermal oxidation, and larger cracks were found after 800 h of exposure. An increase in both ceramic and bond-coat compaction was observed after prolonged high-temperature exposure, and this was sustained by the higher adhesion strength. Moreover, in extreme conditions, under high-temperature thermal shock cycles, the TBC withstands for 1242 cycles at 1200 °C and 555 cycles at 1250 °C.
本文着重研究了通过大气等离子喷涂（APS）沉积的纳米结构热障涂层（TBC）系统的性能，该系统的粘结层在制造过程中产生了层间孔隙。研究了粘结层较高的孔隙率水平作为控制热生长氧化物（TGO）厚度的一种可能方法，因为TGO分布在更大的表面积上，从而降低了长期氧化和高温热冲击过程中面层（TC）剥落的可能性。该TBC系统由纳米结构的氧化钇部分稳定氧化锆（YSZ）作为面层和传统的NiCrAlY粘结层组成。层间孔隙确保了TGO在更大表面积上的形成，而不影响涂层的整体性能。基于在1150°C下进行的长期等温氧化试验，在1150°C长期等温氧化的情况下，层间孔隙不会影响纳米结构TBC的高抗性。陶瓷层在800小时的高温暴露下保持完好，未出现大面积剥落。等温氧化400小时后，在陶瓷涂层中发现了细小裂纹，暴露800小时后发现了更大的裂纹。长时间高温暴露后，观察到陶瓷层和粘结层的致密化程度均有所增加，并且这是由更高的粘结强度维持的。此外，在极端条件下，即在高温热冲击循环下，TBC在1200°C下能承受1242次循环，在1250°C下能承受555次循环。
