In this study, first, yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) with CoNiCrAlY bond coats both were fabricated on IN718 superalloy substrate, using air plasma spraying (APS) techniques. In order to understand the actual microstructural morphological behavior, phase stability, and thermal cycling behaviors of 8YSZ TBCs were characterized by field emission spectroscopy equipped scanning electron microscopy (FESEM), differential scanning calorimetry (DSC) and thermal cycling test. DSC results confirmed the basic reason of selecting the high cycling temperature. The crack initiation and propagation under thermal stresses due to temperature differences from maximum temperature of 1100^∘C to cooling medium; here, air cooling and water quenching are used. Arising from either edges or corners it was observed serious problem which is restraining thermal cycling lifetime of TBCs, indicating failure mechanism is independent from operating parameters of thermal cycling test. However, in comparison to water-cooled thermal fatigue life, air-cooled thermal fatigue lifetime was 2.36 times better.

中文翻译：

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受热循环系统中冷却介质影响的 APSED TBCS 的行为

在这项研究中，首先，使用空气等离子喷涂 (APS) 技术在 IN718 高温合金基底上制造了具有 CoNiCrAlY 粘结涂层的氧化钇稳定氧化锆 (YSZ) 热障涂层 (TBC)。为了了解 8YSZ TBCs 的实际微观结构形态行为、相稳定性和热循环行为，通过配备场发射光谱的扫描电子显微镜 (FESEM)、差示扫描量热法 (DSC) 和热循环测试来表征。DSC结果证实了选择高循环温度的根本原因。与最高温度 1100 的温差导致的热应力下裂纹的萌生和扩展^∘C为冷却介质；在这里，使用空气冷却和水淬。观察到从边缘或角落出现的严重问题是限制 TBC 的热循环寿命，这表明故障机制与热循环测试的操作参数无关。然而，与水冷热疲劳寿命相比，风冷热疲劳寿命要好 2.36 倍。