Alloying of Yb–Cu and Yb–Ag utilizing liquid ammonia metal solutions of ytterbium

Abstract

In the course of the studies on preparation of novel compounds using the dissolution of Eu or Yb metals in liquid ammonia, the formation of Yb–Cu and Yb–Ag intermetallic films has been found. When Cu or Ag metal powders were placed in a reactor containing a solution of Yb metal in liquid ammonia, the dissolved Yb readily react with the Cu or Ag metal particles to form surface alloy compounds. X-ray diffraction of Yb–Cu showed that upon thermal treatment above 673K, the Yb metal deposited on the Cu particles reacted together to be transformed into the YbCu6.5 intermetallic compound. A characteristic endothermic peak at 749K, due to alloying of Yb–Cu, was observed by the differential scanning calorimeter measurements. By use of the high reactivity of liquid ammonia metal solutions of ytterbium, it was found that the ytterbium intermetallic films were readily formed under mild conditions. Yb–Cu and Yb–Ag exhibited enhanced catalytic activity for the hydrogenation of ethene as a result of alloying.