Preparation of continuous zirconia fibres from polyzirconoxane synthesized by the facile one-pot reaction

A one-pot reaction of zirconium oxychloride octahydrate (ZOC) with ethyl acetoacetate (Hetac) in the presence of triethylamine was investigated. The reaction was carried out in molar ratios of Hetac/ZOC = 1.0, 1.5, 2.0 to give highly viscous solutions with good spinnability and stability to self-condensation. Polyzirconoxanes (PZOs) were isolated as white powders by reprecipitation of the solutions with tetrahydrofuron (THF)-hexane that were soluble in acetone, methanol and THF. The molecular weight of PZO was Mn = 1000-2000, and was dependent on the molar ratio and the reaction time. Dry spinning of the solution (Hetac/ZOC = 1.5) containing 3 mol% tris(acetylacetonato)yttrium [Y(acac)(3)] gave continuous precursor fibres (3.0Y-PZO). Yttria stabilized zirconia fibres of 12-18 mu m diameter with a tensile strength of 1.4 GPa were obtained by heat treatment of the 3.0Y-PZO at 1100 or 1200 degrees C. The fibre consisted of submicrometre-sized particles of tetragonal crystallites. (C) 1998 Chapman & Hall.