Experimental and theoretical investigations in alkaline earth-zinc-aluminum intermetallic systems

Abstract

<p>A series of intermetallic compounds in alkaline earth - zinc - aluminum (Ae-Zn-Al) systems were studied. The concept of valence electron concentration (vec) was used as a guide to synthesize new compounds with vec ranges between 2.0 and 4.0. The investigated systems include: (1) BaZn10Al2 (vec = 2.18). (2) (Li,Mg)1.63(ZnAl)3.37 (2.0 ≤ vec ≤ 2.34). (3) AeZnxAl4-x (3.0 < vec < 3.5, Ae = Ca-Ba, 0.0 ≤ x ≤ 2.0) and (4) Ba14 Zn5Al22 (vec = 3.85). Both experimental and theoretical investigations were performed on all identified compounds to understand their structure, phase width, site preference, and physical properties. Theoretical calculations also provide hints for synthesis and characterization of new intermetallic compounds. The structure features of Ae-Zn-Al intermetallics indicate that the dimensionality of Zn-Al networks is reduced as the vec is increased. The site preference for different elements is affected by coordination environments, bonding characters of interatomic contacts, and vec.</p>