Sebastian J T, Rüsing J, Hellman O C, Seidman D N, Vriesendorp W, Kooi B J
Department of Material Science and Engineering, Northwestern University, Evanston, IL, USA.
Ultramicroscopy. 2001 Oct;89(1-3):203-13. doi: 10.1016/s0304-3991(01)00140-1.
Three-dimensional atom-probe (3DAP) microscopy has been applied to the study of segregation at ceramic/metal (C/M) interfaces. In this article, results on the MgO/Cu(X) (where X = Ag or Sb) systems are summarized. Nanometer-size MgO precipitates with atomically clean and atomically sharp interfaces were prepared in these systems by internal oxidation. Segregation of the ternary component (Ag or Sb) at the MgO/Cu heterophase interface was enhanced by extended low-temperature anneals. Magnesia precipitates in the 3DAP reconstructions were delineated as isoconcentration surfaces, and segregation of each ternary component at the C/M interfaces was analyzed with the proximity histogram method developed at Northwestern University. This method allows the direct extraction of the Gibbsian interfacial excess of solute at the C/M interfaces from the experimental data. A value of (3.2+/-2.0) x 10(17)m(-2) at 500 degrees C is obtained for the segregation of Ag at a MgO/Cu(Ag) interface, while a value of (2.9+/-0.9) x 10(18) m(-2) at 500 degrees C is obtained for the segregation of Sb at a MgO/Cu(Sb) interface. The larger Gibbsian excess for Sb segregation at this ceramic/metal heterophase interface is most likely due to the so-called pdeltaV effect.
三维原子探针（3DAP）显微镜已应用于陶瓷/金属（C/M）界面偏析的研究。本文总结了MgO/Cu(X)（其中X = Ag或Sb）体系的研究结果。通过内氧化在这些体系中制备了具有原子清洁且原子尖锐界面的纳米尺寸MgO析出物。通过长时间低温退火增强了三元组分（Ag或Sb）在MgO/Cu异相界面处的偏析。在3DAP重建中，氧化镁析出物被描绘为等浓度表面，并使用西北大学开发的邻近直方图方法分析了每个三元组分在C/M界面处的偏析。该方法允许从实验数据中直接提取C/M界面处溶质的吉布斯界面超额。在500℃时，MgO/Cu(Ag)界面处Ag的偏析值为(3.2±2.0)×10¹⁷ m⁻²，而在500℃时，MgO/Cu(Sb)界面处Sb的偏析值为(2.9±0.9)×10¹⁸ m⁻²。在该陶瓷/金属异相界面处，Sb偏析的吉布斯超额较大很可能是由于所谓的pδV效应。
