| 수성 알루미나/탄화규소 슬러리의 동결주조와 층상복합체의 제조: (I) 슬러리의 분산과 유동성 |
| 양태영, 조용기, 김영우1, 윤석영, 박홍채 |
부산대학교 재료공학부
1포항산업과학연구원 기능성재료연구팀 |
| Freeze Casting of Aqueous Alumina/Silicon Carbide Slurries and Fabrication of Layered Composites: (I) Dispersion and Rheology of Slurries |
| Tae-Young Yang, Yong-Ki Cho, Young-Woo Kim1, Seog-Young Yoon, Hong-Chae Park |
School of Materials Science and Engineering, Pusan National University
1Functional Materials Research Team, Research Institute of Industrial Science and Technology |
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| ABSTRACT |
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Zeta potential, sedimentation bulk density and rheology in the dispersion system have been studied in terms of solid loading (40-55 vol%), and types of additives. Ammonium polymethacrylate, glycerol, ethoxylated acetylenic diol, and polyvinyl alcohol have been used as the dispersant, cryo-protectant, surfactant, and binder, respectively. Sedimentation density greatly increased upon adding dispersant; the effect was more pronounced with ionic alumina suspension compared with covalent silicon carbide. With further addition of cryo-protectant and surfactant to dispersant, the sedimentation density increased somewhat. The suspension viscosity generally behaviored in an opposite manner to the sedimentation density, i.e., high sedimentation gave low high-shear viscosity, indicative of low order structure formation in the suspended particles. Shear rate rheology in shear rate of $2-300;sec^{-1}$ showed a shear thinning and its onset began at similar shear rate (${sim}100;sce^{-1}$), regardless of solid loading. |
| Key words:
Alumina/silicon carbide nano-powder/silicon carbide whisker, Sedimentation density, Rheology, Shear thinning |
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