On the miscibility gap of Cu-Ni system

TL;DR

This study experimentally identifies a new miscibility gap in the Cu-Ni system using nano-layered thin films, providing the first measurement of atomic fractions across the entire composition range and revealing a maximum at 800 K.

Contribution

First experimental determination of the Cu-Ni miscibility gap across all compositions using secondary neutral mass spectrometry in nano-layered films.

Findings

Maximum of the miscibility curve at 800 K for Cu50%Ni50%

First measurement of atomic fractions in the entire composition range

New evidence of a miscibility gap in Cu-Ni system

Abstract

The existence of the miscibility gap in the Cu-Ni system has been an issue in both computational and experimental discussions for half a century [Chakrabarti et al., Phase diagrams of binary nickel alloys, ASM, 1991]. Here we propose a new miscibility gap in the Cu-Ni system measured in nano-layered thin films by Secondary Neutral Mass Spectrometry. The maximum of the symmetrical miscibility curve is around 800~K at Cu50%Ni50%. To our best knowledge, this is the first experiment determining the miscibility from the measurement of the atomic fraction of Copper and Nickel in the whole composition range. Needless to say that Ni, Cu and its alloys are important in various fields, accordingly this result affects different areas to understand materials sciences.