Improved Cr2O3 adhesion by Ce ion implantation in the presence of interfacial sulfur segregation
Improved Cr2O3 adhesion by Ce ion implantation in the presence of interfacial sulfur segregation
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DOI：
10.1016/j.actamat.2006.07.047
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发表时间：
2007
期刊：
影响因子：
9.4
通讯作者：
M. Li;P. Hou
中科院分区：
文献类型：
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作者：
M. Li;P. Hou
抛光预氧化的 Ni-20Cr 合金以 1×1017ions/cm2 的剂量进行 Ce 注入，然后在 1050°C 的空气中进行氧化。使用拉伸测试和带有原位划痕装置的扫描俄歇显微镜分别测定了氧化物-合金界面处的氧化物粘附力和硫偏析程度。未注入的 Ni-20Cr 氧化物失效的临界载荷最低，而注入预制氧化物的氧化物破坏的临界载荷稍高。直接在植入 Ce 的 Ni-20Cr 上形成的氧化物在拉力测试中从未失败，表现出最强的氧化皮附着力；然而，在所有界面上都发现了相似数量的界面硫，这些硫在氧化过程中从合金中分离出来。还发现添加 Ce 可以降低氧化速率并影响氧化皮 - 合金界面处的空隙程度。这表明氧化物生长机制的变化减少了界面空隙的数量，并且与 Al2O3 不同，这些因素对于 Cr2O3 氧化皮粘附力比硫偏析到氧化皮-合金界面更重要。
As-polished and preoxidized Ni–20Cr alloys were Ce-implanted with a dosage of 1×1017ions/cm2, then subsequently oxidized at 1050°C in air. The oxide adhesion and the extent of sulfur segregation at the oxide–alloy interface were determined, respectively, using tensile pull testing and scanning Auger microscopy with an in situ scratch device. The critical load for oxide failure was the lowest on the unimplanted Ni–20Cr, and was slightly higher on those with implantation made into a preformed oxide. Oxides that formed directly on Ce-implanted Ni–20Cr never failed under the pull test, which showed the strongest scale adhesion; however, similar amounts of interfacial sulfur, which segregated from the alloy during oxidation, were found at all interfaces. Ce additions were also found to reduce the oxidation rate and affect the extent of voids at the scale–alloy interface. It is suggested that the change in the oxide growth mechanism reduces the number of interfacial voids and, unlike Al2O3, these factors are more important for Cr2O3scale adhesion than sulfur segregation to the scale–alloy interface.