Gelling behavior of MgAl2O4 slurries with a common dispersant |
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| Authors: | Mengwei Liu Jin Zhao Shunzo Shimai Dan Han Jian Zhang Shiwei Wang |
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| Affiliation: | 1. State Key Laboratory on High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China;2. State Key Laboratory on High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China |
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| Abstract: | MgAl2O4 transparent ceramics were shaped by a commonly used polyacrylic acid (PAA), which acted as both dispersant and gelling agent. The spinel slurries were prepared by ball-milling MgAl2O4 powder, PAA, and water in an attrition mill. The gelling of slurries happened at room temperature in air atmosphere without any other organic additive. The gelling mechanism was the formation of chelates between Mg2+ and carboxyl groups (-COO?) of PAA. The frequency-based testing method was applied to investigate the gelling process of the as-prepared slurry. In addition, a novel in situ characterization method based on a modified indentation testing was invented to better understand the strengthening of the wet green body with time and to guide when demolding could be carried out. After sintering, transparent MgAl2O4 ceramics with high in-line transmittance were resulted. |
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| Keywords: | Gel casting gelling behavior slurries spinels |
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