Phase relations and crystal structures in the Ag–Ga system

• Published in: Journal of alloys and compounds 2000-02, Vol.297 (1), p.144-155
• Main Authors: Gunnæs, A.E, Karlsen, O.B, Olsen, A, Zagierski, P.T
• Format: Article
• Language: English
• Subjects: Ag–Ga system; Alloys; Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; DTA; Exact sciences and technology; Materials science; Metals. Metallurgy; Phase diagram; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of metals and alloys; Physics; PXD; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; TEM
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(99)00572-1

The Ag–Ga phase diagram and the ζ-Ag 2Ga↔ζ′-Ag 2Ga transformation have been investigated by use of optical, scanning and transmission electron microscopy combined with X-ray powder diffraction and thermal differential analysis. On the basis of the present study a new equilibrium phase diagram for the Ag–Ga system is proposed. Only two intermetallic phases are found in the Ag–Ga system: ζ′ and ζ. The compositional change of Ga in ζ′ is described by replacing Ga atoms in 1b position in space group P 62m with Ag atoms. In alloys having 25–40 wt.% Ga, the high temperature ζ-Ag 2Ga is found to decompose into a Ga-rich liquid and solid ζ′-Ag 2Ga at 302°C. In Ga-poor alloys (15 wt.%), the high temperature ζ-Ag 2Ga is found to decompose into α-Ag and liquid at 611°C and into α-Ag and ζ′-Ag 2Ga at 395°C.