In this work, hot corrosion behavior of air plasma sprayed La_0.8Ba_0.2TiO_3-δ (LBT)-YSZ double-ceramic-layer thermal barrier coating exposed to Na₂SO₄ + V₂O₅ molten salt at 900 °C for 20 h was investigated. The phase characterization and microstructural evolution analysis of the coating was carried out after the hot corrosion test by using X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the LBT-YSZ coating possessed excellent hot corrosion resistance compared with the conventional pure YSZ coating. The conventional pure YSZ coating was completely destroyed after the 10 h test due to the volume change resulting from the adverse phase transition. However, the situation for the LBT-YSZ coatings is completely opposite. The LBT-YSZ coating could prevent the YSZ interlayer underlying the LBT overlayer from densification for at least 20 h. In the LBT overlayer, the double-reaction-layer composed of under dense layer and upper porous layer was formed. In particular, the continuous dense layers with a thickness of ~100 μm formed after 10 h, effectively arresting further penetration of the molten salt. In addition, affected by the diffusion extent of SO₃ gas, the corrosion products of porous layer were composed of Ba₂V₂O₇, LaVO₄, TiO₂ and BaSO₄, while those of dense layer consisted of Ba₂V₂O₇, LaVO₄ and TiO₂. The specific mechanism by which the corrosion reaction occurred was proposed based on Lewis acid-base rule and thermodynamics.

在这项工作中，暴露于Na ₂ SO ₄  + V ₂ O ₅的空气等离子喷涂La _0.8 Ba _0.2 TiO3 _-δ（LBT）-YSZ双陶瓷层热障涂层的热腐蚀行为研究了在900°C下熔盐20 h的情况。在热腐蚀试验之后，通过使用X射线衍射（XRD），扫描电子显微镜（SEM）和X射线光电子能谱（XPS）进行涂层的相表征和微观结构演变分析。结果表明，与传统的纯YSZ涂层相比，LBT-YSZ涂层具有优异的抗热腐蚀性能。常规纯YSZ涂层在10 h试验后由于不良相变导致体积变化而被完全破坏。但是，LBT-YSZ涂层的情况完全相反。LBT-YSZ涂层可以防止LBT覆盖层下面的YSZ夹层致密化至少20小时。在LBT覆盖层中，形成由下致密层和上多孔层组成的双反应层。特别是，在10小时后形成了厚度约为100μm的连续致密层，有效阻止了熔盐的进一步渗透。另外，受SO的扩散程度的影响_在3种气体中，多孔层的腐蚀产物由Ba ₂ V ₂ O ₇，LaVO ₄，TiO ₂和BaSO _4组成，而致密层的腐蚀产物由Ba ₂ V ₂ O ₇，LaVO ₄和TiO _2组成。根据路易斯酸碱定律和热力学，提出了发生腐蚀反应的具体机理。