Mo-Re合金表面MoSi2和Gd2Zr2O7复合涂层的显微组织和热性能

Microstructure and Thermal Properties of MoSi2 and Gd2Zr2O7 Composite Coatings on Mo-Re Alloy

摘要:

在钼铼合金热端部件表面制备了超高温双层隔热涂层（TBCs），根据热膨胀系数及涂层功能设计并通过大气等离子喷涂技术完成了MoSi₂-Gd₂Zr₂O₇的双层TBCs的制备，并对其微观组织、力学性能及热学性能进行分析。结果表明：制备出的双层复合TBCs结合力良好，界面未出现明显裂纹。相较于MoSi₂涂层断裂韧性低（0.88 MPa·m^1/2），Gd₂Zr₂O₇涂层的断裂韧性更高（1.74 MPa·m^1/2），抗裂纹传播能力更强。制备的MoSi₂-Gd₂Zr₂O₇复合涂层孔隙率高（39%）、导热系数低（1.020 W·(m·K)^-1，1200 ℃）、热扩散系数低（0.249 mm²/s，1200 ℃），氧空位浓度高，保证了良好的隔热性能。

Abstract:

Dual-layer thermal barrier coatings (TBCs) with ultrahigh temperature resistance were prepared on the surface of molybdenum-rhenium alloy hot-end components. The preparation of the MoSi₂-Gd₂Zr₂O₇ dual-layer TBCs was designed based on the coefficient of thermal expansion and the coating functionality, and it was completed using atmospheric plasma spraying technique. The microstructure, mechanical properties, and thermal properties were analyzed. Results indicate that the adhesion of the prepared dual-layer composite TBCs is excellent, and no noticeable cracks appear at the interface. Compared with the MoSi₂ coating with a low fracture toughness (0.88 MPa·m^1/2), the Gd₂Zr₂O₇ coating exhibits higher fracture toughness (1.74 MPa·m^1/2) and stronger resistance to crack propagation. The prepared MoSi₂-Gd₂Zr₂O₇ composite coatings have a high porosity (39%), low thermal conductivity (1.020 W·(m·K)^-1, 1200 °C), and low thermal diffusivity (0.249 mm²/s, 1200 °C). Additionally, they possess a high oxygen-vacancy concentration, which ensures excellent insulation performance.