The manufacture of yttrium aluminium garnet (YAG) fibres by blow spinning from a sol-gel precursor

Three different systems consisting of a yttria sol and alumina sols were investigated and gel fibres were successfully spun which on subsequent heating produced ceramic fibres of yttrium aluminium garnet (YAG). The fibres were characterised by various techniques. The fibres were found to begin forming YAG between 700-750 degrees C and it was present as a single phase between 750-800 degrees C, the lowest reported temperature for the crystallisation of this material. The fibres had no discernible grain structure and the average crystallite size was calculated to be! only 20nm at this temperature; however, the fibres were estimated to remain 20% porous tip to 1200 degrees C. The fibres were handleable after YAG crystallisation, but more investigation is required into sintering and the development of high temperature properties. (C) 1998 Elsevier Science Limited. All rights reserved.