Solubility and magnetic properties of Ag−Co−Si alloy synthesized by mechanical alloying and annealing Löslichkeit und magnetische Eigenschaften von durch mechanisches Legieren und Glühen hergestellten Ag−Co−Si-Legierungen

Abstract

This present work concerns the effect of ternary addition of non-metallic and diamagnetic silicon on the metastable solubility of the immiscible silver-cobalt system during the course of ball milling, annealing of the ball milled samples and the corresponding magnetic properties. It should be noted that silicon has a smaller goldsmidt radius (111 pm) than silver (144 pm) and silicon⁺⁴ has more valence electrons than silver⁺¹. Keeping the objectives of the current study in mind, silicon may thus be considered as an option for ternary addition, in contrast to metallic components. An attempt has been made to examine the phase changes that occurred in the 50 silver-40 cobalt-10 silicon (atom percent) system during ball milling and the subsequent isothermal annealing of the ball milled product. Phase evolution during mechanical alloying and isothermal annealing is identified by means of x-ray diffraction, differential thermal analysis, high resolution transmission electron microscopy and magnetic measurements. The addition of silicon facilitates cobalt‘s formation of a metastable alloy with copper after 50 hours of ball milling. Annealing significantly improves the magnetic characteristics of materials that have been ball milled; the optimal combination of magnetic properties was obtained after an hour of annealing at 550 °C.