Effect of chemical additives on microfibre formation from SiO vapour condensed in flowing gas streams

Abstract

SiO vapour has been allowed to condense from flowing gas streams in the presence of a wide range of inorganic and organic vapour species to determine the effect of these species on the known habit of SiO of condensing to form microfibres of potential use as reinforcing fillers. Major changes in fibre morphology have been observed on condensation of SiO in an N₂ stream containing gaseous AlCl₃, GeCl₄ or C₂H₂, or by condensation of SiO with other molecular species formed when Ga₂O₃–SiO₂–Si, In₂O₃–SiO₂–Si or GeO₂–SiO₂–Si mixtures were heated in N₂ or B–SiO₂ was heated in H₂. The fibre morphology changed surprisingly little when SiO was condensed with vapours of transition-metal halides. The products were studied by transmission electron microscopy (TEM), IR, X-ray photoelectron spectroscopy (XPS) and powder XRD. The work establishes that condensing SiO is an exceptionally versatile microfibre-forming system.