A determination of the temperature dependence of segregation for A 56 a/o Ni−Co alloy on (111) and (210) faces using AES

The dependence of surface segregation on temperature has been explored for an fcc 56 a/o Ni−Co alloy in the range 773–1000 K. The enthalpy and entropy of segregation for a (111) face are reported as 17.4±1.6 kJ/mol and +41.1±1.8 J mol·K respectively. A temperature dependence is also reported for a (210) face but the appropriateness of assigning an enthalpy and entropy are questioned. An improvement in the capability to simulate spectra of this system to ±0.5% is also reported as well as an investigation into the usefulness of scratched alloys as standards for quantitation of surfaces.