The oxidation rates of Ni–Al and Ni–Al–Cr alloys in an Ar–12 vol%H2O atmosphere during heating were determined by a hydrogen sensor and an oxygen pump sensor installed at the subsequent stage. The effect of Cr on the Ni–Al alloy was studied. As a result, the Ni–5 wt%Al showed a sharp increase in oxidation rate at 900 °C. Thereafter, a linear increase in the oxidation rate was observed during its heating. On the other hand, the Ni–5 wt%Al–5 wt%Cr alloy showed a sharp increase in the oxidation rate at 900 °C, but the value was lower than that of Ni–5 wt%Al. During the heating from 900 to 1250 °C, it showed a discontinuous behavior. In the cross-sectional structure, a thick oxide and thin oxide were formed. For the thin part, NiAl2O4 was formed on the surface and Al2O3 was formed below it. The oxidation rate of Ni–5 wt%Al–10 to 20 wt%Cr alloys when the temperature reached 900 °C was very low. For the cross-sectional structure, Cr oxide was formed on the surface, and Al2O3 was formed below it. When Cr oxide was formed on the surface, a sharp decrease in the oxidation rate was observed during the heating. It is considered that the oxidation rate decreases by the transformation of Al2O3 from θ to α during the heating. Furthermore, the rate of oxidation during the heating decreased more when chromium oxide was formed than when Ni oxide was formed on the surface. This revealed the relationship between the oxidation rate and the effect of Cr on the Al2O3.

中文翻译：

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使用氢传感器和氧泵传感器研究 Ni–5 wt%Al–X wt%Cr 合金的氧化铝形成和氧化速率

Ni-Al 和 Ni-Al-Cr 合金在加热过程中在 Ar-12 vol%H2O 气氛中的氧化速率由安装在后续阶段的氢传感器和氧泵传感器确定。研究了 Cr 对 Ni-Al 合金的影响。结果，Ni-5 wt%Al 在 900 °C 时显示出氧化速率的急剧增加。此后，在加热过程中观察到氧化速率线性增加。另一方面，Ni-5 wt%Al-5 wt%Cr 合金在 900 °C 时的氧化速率急剧增加，但该值低于 Ni-5 wt%Al。在从 900 到 1250 °C 的加热过程中，它表现出不连续的行为。在横截面结构中，形成了厚氧化物和薄氧化物。对于薄的部分，NiAl2O4 形成在表面上，Al2O3 形成在其下方。当温度达到 900 °C 时，Ni-5 wt%Al-10 至 20 wt%Cr 合金的氧化速率非常低。对于横截面结构，在表面形成 Cr 氧化物，在其下方形成 Al2O3。当在表面形成 Cr 氧化物时，在加热过程中观察到氧化速率急剧下降。可以认为，在加热过程中，Al2O3 从 θ 转变为 α，从而降低了氧化速率。此外，当形成氧化铬时，加热过程中的氧化速率比在表面形成氧化镍时降低得更多。这揭示了氧化速率与 Cr 对 Al2O3 的影响之间的关系。在加热过程中观察到氧化速率急剧下降。可以认为，在加热过程中，Al2O3 从 θ 转变为 α，从而降低了氧化速率。此外，当形成氧化铬时，加热过程中的氧化速率比在表面形成氧化镍时降低得更多。这揭示了氧化速率与 Cr 对 Al2O3 的影响之间的关系。在加热过程中观察到氧化速率急剧下降。可以认为，在加热过程中，Al2O3 从 θ 转变为 α，从而降低了氧化速率。此外，当形成氧化铬时，加热过程中的氧化速率比在表面形成氧化镍时降低得更多。这揭示了氧化速率与 Cr 对 Al2O3 的影响之间的关系。