Atomic Scale Studies of Segregation at Ceramic/Metal Heterophase Interfaces

Atom-probe field-ion microscopy was used to measure quantitatively γAg, the absolute values of the Gibbsian interfacial excess of Ag, at semicoherent MgO/Cu(Ag) 222 heterophase interfaces. Atomically clean metal oxide/metal heterophase interfaces were obtained by internal oxidation of a pure ternary Cu(Mg,Ag) single-phase alloy to produce octahedral-shaped MgO precipitates, 10 to 30 nm in diameter, in a single-phase Cu(Ag) matrix. The measured value of γAg at 500 ^∘{}C is (2±0.6)×10¹⁵ atoms cm⁻⁻².