部分稳定氧化锆陶瓷的凝胶注模成型工艺(英文)

PREPARATION OF PARTIALLY STABILIZED ZIRCONIA CERAMIC BY AQUEOUS GELCASTING

用流变学的方法研究了不同条件,如:固相含量、分散剂加入量、烧结助剂、增塑剂等对碱性部分稳定氧化锆(partially stabilized zirconia,PSZ)悬浮体的流变性的影响。结果表明:分散剂含量对悬浮液的流变性能有明显影响,当PSZ固相体积含量为55%时,分散剂加入量(占固相含量的质量分数)应为0.4%。当固相体积含量为50%～56%时,氧化锆碱性料浆呈现剪切变稀行为,具有较低的黏度(在剪切速率为10s-1时,低于50mPa·s)。氧化锆陶瓷碱性料浆(pH>7)在低的剪切速率(<100s-1)时,表现为剪切变稀。凝胶注模法生产的PSZ陶瓷坯体的内部结构是均匀的。

A partially stabilized zirconia （PSZ） ceramic was prepared by aqueous gelcasting. The effects of the zeta potentials, solid loading, dispersant content and milling time on the PSZ suspension were studied. The dispersant content has a remarkable effect on the rheological properties of the suspension. The appropriate dispersant mass fraction for PSZ aqueous slurry with the solid loading of 55% in volume is 0.4%. All suspensions （50%-56% solid loading） exhibit a shear-thinning behavior and relatively low viscosity （less than 50 mPa-s, at a shear rate of 10 s^-1）, which is suitable for casting. The degree of shear thinning and the viscosity at high shear rates increase with the increasing of volume fraction of solid phase. As the milling time is prolonged, the viscosity of the suspension decreases first, and then a plateau appears and the average diameter remains unchanged. When the milling time is shorter than 20 h, the viscosity of the slurry decreases gradually as the time of milling is increased. After 20 h milling, the viscosity of the slurry tends to be consistent. Therefore, the ball milling time should be equal to or more than 20 h in order to obtain a stable suspension at equilibrium. The appropriate time for casting the slurry （idle time） can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing temperature. According to micrographs, the gelcasting green body is homogeneous.