The transient stage of alumina scale formation on alumina-forming alloys is often accompanied by the formation of metastable Al₂O₃ phases that may affect oxidation kinetics and scale microstructure. To clarify the role of dopants on the transient stage of NiAl oxidation, we characterized Al₂O₃ scales on a series of oxidized model β-NiAl samples that were un-doped or doped with additions of Ti, Y, Si, Ti + Y, and Si + Y. Our results confirm that different dopant elements (Ti, Si, and Y) have varied effects on the length of transient oxidation of alumina-forming alloys. Ti and Si accelerated the θ- to α-Al₂O₃ transformation via two different mechanisms. Ti promoted α-Al₂O₃ nucleation, while Si delayed nucleation but accelerated the lateral growth of the α-Al₂O₃ patches. In contrast, Y had little effect on alumina transformation, possibly due to the low Y concentration used in the current study.

在形成氧化铝的合金上氧化铝水垢形成的过渡阶段通常伴随着亚稳态的Al ₂ O ₃相的形成，这可能会影响氧化动力学和水垢的微观结构。为了阐明掺杂剂在NiAl氧化过渡阶段的作用，我们在一系列未掺杂或掺杂有Ti，Y，Si，Ti + Y的氧化模型β-NiAl样品上表征了Al ₂ O ₃鳞片。我们的结果证实，不同的掺杂元素（Ti，Si和Y）对形成氧化铝的合金的瞬态氧化长度有不同的影响。Ti和Si加速θ-到的α-Al ₂ ö ₃通过两种不同的机制转变。钛促进的α-Al ₂ø ₃成核，而延迟的Si成核，但加速了的横向生长的α-Al _2个ö ₃补丁。相反，Y对氧化铝的转化几乎没有影响，这可能是由于当前研究中使用的Y浓度较低。