Abstract
Synthetic process of making yttria stabilized sub-micron zirconia powder was studied by co-precipitation technique at room temperature using zirconyl chloride solution of different concentrations. The effect of concentration on particle agglomeration and sinterability of powder mixed with yttrium nitrate solution as a source of Y2O3 and ammonia as precipitating agent was investigated. Hydrogels of different batches obtained by precipitation reaction were characterized by characterizing particle size and specific surface area, SEM, XRD, TGA and DTA analyses. Hydrogel obtained from low concentrated ZrOCl2 solution showed large particle size and low specific surface area due to hard agglomerate of fine particles and poor sintering behaviour of calcined powder compared to powder obtained from high concentrated solution. Sintering temperature of 1400°C was found to be suitable for optimum densification (96.8% theoretical density) as also optimum flexural strength (∼345 MPa) that was achieved (in case of the calcined gel of agglomerate size 3.7 μm) for powder precipitated from 30 wt% zirconyl chloride solution sintered at 1400°C. This was attributed to small particle size and high specific surface area (compared to other stock solution) of hydrogel precipitated from 30 wt% stock solution. SEM of sintered sample showed fine grained structure with absence of pore.
Published Version
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