低压等离子喷涂NiCoCrAIYTa涂层的抗燃气热冲击性能研究

Comparative Study of NiCoCrAlYTa Coatings After Burner-Rig Test

摘要:

为了保障涡轮叶片材料的抗高温氧化与耐热腐蚀性能，采用低压等离子喷涂技术在航空发动机涡轮叶片试验件上成功制备了NiCoCrAlYTa涂层。通过对不同粉末制备的NiCoCrAlYTa涂层进行1 000 ℃/75 h燃气热冲击试验，研究了带涂层叶片尺寸、涂层表面形貌、相组成和显微组织、涂层厚度和均匀性等性能参数的变化。结果表明：热冲击试验后，不同涂层叶片的整体尺寸未发生显著变化，表明涂层在高温环境下具有稳定的尺寸；涂层表面形成了Al₂O₃膜和NiAl₂O₄尖晶石，保留了较好的结构完整度，这有助于提高涂层的耐腐蚀性能；涂层的物相组成主要包括γ-Ni、γ'-Ni₃Al和少量的β-NiAl，形成了贫Al区、互扩散区、二次反应区等典型微区结构，析出的TCP相为R相，表明在热冲击过程中涂层发生了相变；不同粉末制备的NiCoCrAlYTa涂层均表现出了良好的抗热冲击性能，为航空发动机涡轮叶片的高温应用提供了可行的涂层方案。

Abstract:

The NiCoCrAlYTa coatings were prepared on aero-engine turbine blades samples by low pressure plasma spraying. Different powders were used for the preparation. The burner-rig test was carried out at 1 000 °C for 75 hours. The size of coated blades， the surface morphology， phase composition， microstructure， thickness and uniformity of coatings were investigated. The results showed that there was no significant variation in the overall dimensions of different coated blades after burner-rig test. Al₂O₃ oxide film and NiAl₂O₄ spinel formed on the surface of coatings， which retained good structural integrity. The phase composition of coatings is γ-Ni， γ'-Ni₃Al and a small amount of β-NiAl. Typical microstructure including Al-depleted zone， interdiffusion zone， and secondary reaction zone were observed in the cross-section. The precipitated TCP phase was R phase. The NiCoCrAlYTa coatings prepared by different powders all showed good thermal shock resistance.