TiAl合金表面EB-PVD制备热障涂层及高温抗氧化性能

Preparation and High Temperature Oxidation Resistance of Thermal Barrier Coatings on Ti-Al Alloys by EB-PVD

摘要:

利用EB-PVD技术在TiAl合金表面制备了扩散铝/YSZ热障涂层。采用SEM、EDS和XRD分析了涂层原始及高温氧化后的微观组织及相组成，并测试了高温氧化性能。结果表明：涂层表面YSZ层为致密柱状晶结构，由非平衡四方相t＇-ZrO2组成。TiAl合金沉积了扩散铝/YSZ热障涂层涂层后高温氧化性能显著提高，氧化动力学曲线呈对数变化规律，900℃高温氧化时，氧化速率为2.2?0-5mg/cm2.h。1000℃高温氧化时，氧化速率为1.14?0-3mg/cm2.h。在高温氧化过程中，粘结层与基体之间发生元素扩散，膜基界面消失。在面层与中间粘结层之间形成了均匀连续的热生长氧化物层TGO。

Abstract:

Al-diffusion/YSZ thermal barrier coatings (TBCs) were deposited on Ti-Al alloys by electronic beam-physical vapor deposition (EB-PVD). The microstructure and phase constituent of the TBCs before and after high temperature oxidation were analyzed by SEM, EDS and XRD. And the high temperature oxidation resistance of the TBCs was measured. The results showed that the top YSZ TBCs were composed of non-equilibrium tetragonal t＇-ZrO2, which had a dense columnar microstructure. The high temperature oxidation resistance of TBCs was much higher than that of the substrate. The oxidation kinetics obeyed logarithmic law. The oxidation rates were 2.2?0-5mg/cm2.h and 1.14?0-3mg/cm2.h at 900℃ and 1000℃, respectively. During the high temperature oxidation, the element diffusion was occurred between the bond layers and the substrates and the interfaces were vanished. Thermal grown oxide (TGO) layers were formed between the surface layers and the bond layers.