| 摘要: | Effect of three different surfactants, namely, stearic acid (SA), oleic acid (OA) and 12-hydroxystearic acid (HSA), on the rheological properties of injection-molded alumina suspensions has been investigated over a temperature range of 120-150℃ and a shear-rate range of 1,000-l5,000s^(-1). The suspension mixtures exhibit a pseudoplastic flow behavior and a viscosity (η) order of η(subscript SA)＜η(subscript OA)＜η(subscript HAS) over the shear-rate range tested. A particulate network within the mixtures in a form of powder agglomerates was suspected to play a major role in the flow behavior observed, over which, different levels of powder agglomeration were resulted from the varying surfactants used. A model experiment by repeatedly shearing the suspensions under a fixed stress level partially confirmed the hypothesis. This suggests that the particle network restructured itself upon the shear was applied, leading to breakup of the network and improvements in the particle packing. |
