Synthesis of polycrystalline zirconia fibre with organozirconium precursor
Polycrystalline zirconia fibre was successfully synthesized by pyrolysis of preceramic fibre formed from an organozirconium compound. Dibutoxybis(2, 4-pentadionato)zirconium (BPZ) was polymerized at 150° C and 102 Pa, yielding a viscous polymeric product. The infrared absorption bands of the Zr-O bond changed from separate to coalesced bands after polymerization. The signals of the13C NMR spectrum of BPZ changed from sharp singlets to multiplets after polymerization. The molecular weight of the polymer was between 400 and 1000. The viscosity of polymer was 580 Pa sec at 30° C and a shear rate of 1.0 sec−1. The polymer viscosity decreased with increased temperature from 30 to 60° C. The precursor polymer pyrolysed at 400° C in air was amorphous to X-rays, and crystallized in a mixture of monoclinic and tetragonal phases at 450° C. Tetragonal zirconia was synthesized from the polymer including 4.3 mol % yttrium compound (2.2 mol % yttria) after heat treatment at 1200° C for 1 h. The precursor fibres were pyrolysed to yield fine-grained fibres of tetragonal zirconia at 1200° C for 1 h.
KeywordsZirconia Heat Treatment Pyrolysis Shear Rate Yttria
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