| The alumina -zirconia composite powders were prepared by pyrolysis of the alumina-zirconia precursors obtained by co-precipitation method using NH4Al(SO4)2, ZrOCl2 and (NH4)2CO3 as raw materials. The co-precipitating process conditions and the physical property of precursors during the calcination were studied. The effect of sucrose protection and ball milling on the properties of alumina-zirconia composite powders were investigated, and TG/DSC, XRD, IR, BET and SEM were employed to characterize the alumina-zirconia composite powders. In addition, the sintering behavior of the alumina-zirconia composite powders was also studied after pressing at 160MPa and the microstructure of the sintered body was evaluated with the SEM. The results show:1. The alumina-zirconia composite precursors, with particle sizes in the range of 50-100 nm, can be synthesized under the conditions of reaction temperature 40℃, the pH of reaction system ≥ 9, NH4Al(SO4)2 concentration 0.30 mol/L, (NH4)2CO3 concentration 2.0 mol/L.2. Theα-Al2O3 and tetragonal ZrO2 composite powders with the specific surface area of 5.1 m2/g, particles in the shape of sphericity and particle sizes in the range of 150-200 nm , can be obtained by calcinating the precursors at 1300℃ for 2h.3. The protection of sucrose to alumina-zirconia composite powders could reduce the aggregation of the particles during the calcination.4. The ball milling can effectly break the aggregation among the particles, improve the dispersion and increase the specific surface of the powders.5. Samples for sintering were compacted at a pressure of 160MPa..The alumina-7.5%zirconia composite powders with a relative density of 96% were sintered at 1550℃ for 2h and the alumina-15%zirconia composite powders which... |
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