(17d) Comprehensive Study of Surface Segregation across Ternary Alloy Composition Space: Cuauag

Surface segregation is a phenomenon common to all multicomponent materials, revealing the fact that surface composition can differ significantly from that in the bulk. This is crucial to surface properties including catalysis and adsorption. Comprehensive studies of surface segregation versus bulk composition in ternary alloys are rare because of the need to study many different compositions. In this work, high-throughput low-energy He⁺ ion scattering (LEIS) spectra and energy dispersive X-ray spectra (EDX) were collected from CuAuAg composition spread alloy films (CSAF) under ultra-high vacuum conditions. SEM, XPS and EBSD characterization provide additional micro-structure information. These have been used to quantify surface segregation across the entire composition space. Surface compositions at more than 164 different bulk compositions were measured over a 500-800 K temperature range, with results that are consistent with existing literature on in the segregation binary alloys. The temperature dependency of segregation was evaluated across compositions to quantify segregation enthalpy and entropy from an extended Langmuir-McLean equation. The ability to study surface segregation across ternary alloy composition space with high throughput methods has been again validated, and the impact of thin film dewetting on surface segregation quantification will be discussed.