Molten calcium–magnesium–alumino–silicate (CMAS) infiltration into thermal barrier coatings (TBCs) of gas turbines causes loss of strain tolerance and delamination of the ceramic topcoat. To develop efficient mitigation strategies, it is crucial to understand CMAS infiltration dynamics into the porous topcoat. This study introduces an integrated model, incorporating liquid flow in unsaturated porous structures, heat transfer, and temperature-dependent viscosities, to study CMAS infiltration through TBCs grown by the electron beam physical vapor deposition (EB-PVD) method. The effects of different CMAS compositions, temperature gradients across the topcoat, and coating microstructures are investigated. Our simulation shows that CMAS infiltration exhibits significantly nonlinear dynamics with a fast infiltration rate at the early stage due to high temperature, high pressure gradients, and low viscosity. Neglecting heat transfer enhancement from CMAS by approximating the temperature distribution as linear underestimates the infiltration rate. Fine porous microstructures slow infiltration, and bilayer or multilayer structures, consisting of variable column and pore sizes, combine the advantages of an increased hydraulic resistance to infiltration and lower capillary pressures. Such heterogeneous structures can delay early-stage infiltration by manipulating the layer thickness and arrangement. It is anticipated that the quantitative information and advanced understanding obtained would benefit the development of CMAS-resistant EB-PVD TBC topcoats.

钙-镁-铝硅酸盐（CMAS）熔渗到燃气轮机的热障涂层（TBC）中会导致应变容差的损失和陶瓷面涂层的分层。为了制定有效的缓解策略，了解CMAS渗透到多孔面漆中的动力学至关重要。这项研究引入了一个集成模型，该模型结合了不饱和多孔结构中的液体流动，热传递和温度依赖性粘度，以研究通过电子束物理气相沉积（EB-PVD）方法生长的TBC的CMAS渗透。研究了不同CMAS组成，面涂层上的温度梯度以及涂层微观结构的影响。我们的模拟表明，由于高温，高压梯度和低粘度，CMAS渗透表现出明显的非线性动力学，并且在早期具有快速的渗透速率。通过将温度分布近似为线性，忽略了CMAS的传热增强，低估了渗透率。精细的多孔微结构减慢了渗透速度，而由可变的色谱柱和孔径组成的双层或多层结构则具有增加了对渗透的抗水压性能和较低的毛细管压力的优势。这样的异质结构可以通过控制层的厚度和排列来延迟早期渗透。预计获得的定量信息和高级理解将有助于开发耐CMAS的EB-PVD TBC面漆。