Syntheses, crystal structures and Si solubilities of new layered carbides Zr 2Al 4C 5 and Zr 3Al 4C 6

Abstract

Two types of new ternary carbides, Zr 2Al 4C 5 and Zr 3Al 4C 6, have been synthesized and characterized by X-ray powder diffraction. The crystal structures were refined from laboratory X-ray powder diffraction data (Cu Kα 1) using the Rietveld method. These carbides form a homologous series with the general formula (ZrC) m Al 4C 3 ( m=2 and 3). The crystal structures can be regarded as intergrowth structures where the Al 4C 3-type [Al 4C 4] layers are the same, while the NaCl-type [Zr m C m +1] layers increase in thickness with increasing m value. The new carbides are most probably the end members of continuous solid-solutions (ZrC) m [Al 4− x Si x ]C 3 with 0⩽ x⩽0.44.