部分稳定氧化锆陶瓷的凝胶注模成型工艺_英文_

硅酸盐学报

· 1620 ·2008年

部分稳定氧化锆陶瓷的凝胶注模成型工艺

仝建峰，陈大明

(北京航空材料研究院，先进复合材料国防科技重点实验室，北京 100095)

摘要：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10 s–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。

关键词：部分稳定氧化锆；凝胶注模；流变特性

中图分类号：O373 文献标识码：A 文章编号：0454–5648(2008)11–1620–05

PREPARATION OF PARTIALLY STABILIZED ZIRCONIA CERAMIC BY AQUEOUS GELCASTING

TONG Jianfeng，CHEN Daming

(The National Key Laboratory of Advanced Composite Materials, Beijing Institute of Aeronautical Materials,

Beijing 100095, China, Beijing 81–3 100095, China)

Abstract: 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 50mPa·s, at a shear rate of 10s–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 de-creases first, and then a plateau appears and the average diameter remains unchanged. When the milling time is shorter than 20h, the viscosity of the slurry decreases gradually as the time of milling is increased. After 20h milling, the viscosity of the slurry tends to be consistent. Therefore, the ball milling time should be equal to or more than 20h 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.

Key words: partially stabilized zirconia; gelcasting; rheologic property

Gelcasting is an attractive new ceramic forming proc-ess for making high-quality, complex-shaped ceramic bodies.[1–6] Gelcasting has many distinct advantages compared with conventional ceramic forming processes such as dry pressing, slip casting, tape casting, and injec-tion molding, and it is a near-net-shape forming process. Its products have high green density, low levels of or-ganic additives and machinability in the green state due to a high strength.[7–15]

Both non aqueous and aqueous solvents can be used in gelcasting. But aqueous systems are preferred be-cause the use of water as the solvent has many advan-tages, e.g., less departure from traditional ceramic processing and no environmental problems for disposal. In aqueous gelcasting, acrylamide and methylene bis-acrylamide are commonly used to make monomer solu-tions.[11–18]

According to previous studies,[1–21 the composition of monomer solution, the amounts of initiator and catalyst added, and the temperature and humidity of the drying atmosphere are important processing parameters to be controlled for optimum gelcasting. In this work, a par

收稿日期：2008–04–25。修改稿收到日期：2008–07–03。基金项目：国家自然科学基金(50672091)资助项目。

第一作者：仝建峰(1972—)，男，博士，高级工程师。Received date:2008–04–25. Approved date: 2008–07–03. First author: TONG Jianfeng (1972–), male, doctor, senior engineer. E-mail: jftong@

第36卷第11期2008年11月

硅酸盐学报

JOURNAL OF THE CHINESE CERAMIC SOCIETY

Vol. 36，No. 11

November，2008