影响氧化铝水基料浆流变学特性的关键因素

用流变学的方法在RV-20型流变仪上研究不同条件,如:固含量、分散剂加入量、烧结助剂、增塑剂等对碱性氧化铝悬浮体的流变性的影响.结果表明:氧化铝陶瓷碱性料浆(pH＞7)在低的剪切速率(＜100 s-1)时,表现为剪切变稀.在水基料浆中添加MgO时,会发生强烈的水合反应,导致料浆失去流动性.增塑剂甘油的加入导致料浆粘度升高的幅度是有限的,不会对料浆固含量和浇铸工艺造成显著不利的影响.加入水溶性丙烯酸乳液后,在低的剪切速率下,料浆仍然呈现剪切变稀行为,随着乳液含量的增加,料浆的静态粘度逐渐增大.分散剂聚丙烯酸氨的加入量对料浆的稳定性具有显著的影响.在分散剂的加入量为固相质量的0.8%左右时,分散剂在陶瓷颗粒表面形成饱和吸附,此时料浆的稳定性达到了最佳状态.

KEY FACTORS AFFECTING THE RHEOLOGICAL BEHAVIOR OF Al2O3 AQUEOUS SLURRY

The rheological properties of Al2O3 aqueous slurry, pH in more than 7 were examined by means of the rheological method with RV-20 rheometer. The effects of the solid loading, contents of dispersant, sintering additives and plasticizer on the rheological properties were investigated. It was found that Al2O3 alkaline slurry shows shear thinning behavior at lower shear rates (<100 s-1). After the addition of MgO, hydrolyzation occurred in the aqueous slurry, which could cause the slurry to lose fluidity. The viscosity of the slurry was changed slightly when glycerol was used as a plastic additive, which would not affect the solid loading and casting procedure. When aqueous acrylic acid latex was added, the Al2O3 slurry also showed a shear thinning behavior at lower shear rates (<100 s-1). Furthermore, the static viscosity of Al2O3 slurry shows an increase with the increase of the content of aqueous latex. The dispersant content has a remarkable effect on the stability of the Al2O3 slurry. When the dispersant polyacrylic acid-NH3 content is 0.8% of the mass fraction of the solid phase, the adsorbed state of ceramic powder surface is saturated, so the suspension of Al2O3 slurry reaches maximum stability.