Ni-CeO2复合镀层厚度对δ-Ni2Al3-CeO2/Ni-CeO2涂层体系扩散行为的影响

在Ni基体电沉积不同厚度的Ni-CeO₂复合镀层并对其进行620 °C低温渗铝，制备了剩余复合镀层厚度分别约为10和45 μm厚的δ-Ni₂Al₃-CeO₂/Ni-CeO₂涂层体系。1000 °C真空退火5 h后，以上两种涂层体系均可在铝化物/镀层界面形成CeO₂富集层。但剩余复合镀层厚度为10 μm的涂层体系由于氧化物富集程度不足，涂层退化程度较剩余复合镀层厚度为45 μm的涂层体系严重。可见，在镀层氧化物颗粒含量一定的情况下，渗铝后剩余镀层厚度是影响扩散障有效性的重要因素。

Influence of Thickness of Electrodeposited Ni-CeO2 Film on Interdiffusion of δ-Ni2Al3-CeO2/Ni-CeO2 Coating System and Substrate at High Temperature

Ni-CeO₂ composite films with different thicknesses were electrodeposited on Ni substrate and then aluminized at 620 ℃. Accordingly, two coating (δ-Ni₂Al₃-CeO₂/Ni-CeO₂) systems consisted of an outer portion of δ-Ni₂Al₃-CeO₂ and an inner portion of remaining Ni-CeO₂ films of ca 10 and 45 μm respectively in thickness were prepared. After vacuum annealing at 1000 ℃ for 5 h, the above two coating systems all formed a CeO₂-rich layer in between the outer aluminide coating and the inner Ni-CeO₂ film. However, the degradation of the coating system with the inner Ni-CeO₂ film of 10 μm was more serious than that of 45 μm due to the insufficient oxides enrichment at the interface of aluminide/Ni-CeO₂. It can be seen that the thickness of the remaining inner Ni-CeO₂ film after aluminizing is an important factor responsible to the effectiveness of diffusion barrier for the prepared Ni-CeO₂ film containing a designed amount of CeO₂ particles.