Macroporous ZrO2/Ti composite foams by aqueous gelcasting of particle-stabilized emulsions

Autor: Wenjea J. Tseng, Kai-Ting Hsu
Rok vydání: 2016
Předmět:
Zdroj: Advanced Powder Technology. 27(3):839-844
ISSN: 0921-8831
DOI: 10.1016/j.apt.2015.11.002
Popis: This study aims to demonstrate a general process for the fabrication of macroporous oxide/metal composite foams through aqueous gelcasting of Pickering emulsions. Composite of yttria-stabilized zirconia/titanium (ZrO 2 /Ti) was selected as the model material. The process involves tuning of wettability of the ZrO 2 particles through selective adsorption of organic sodium bis(2-ethylhexyl) sulfosuccinate on the particle surface so that the hydrophobic ZrO 2 particles were able to reside preferentially at the air–water interface during mechanical foaming. The hydrophilic Ti particles, on the other hand, were designed to “stay” between the ZrO 2 -stabilized bubbles to form struts of the foam together with the ZrO 2 particles not attached at the interface. Composite foams of binary particulate mixtures were then shaped into desired geometries by freeze gelcasting in which addition of agar was used as the shape-setting agent to avoid phase segregation due to the density and wettability difference. Porous ZrO 2 /Ti composite foams of various ZrO 2 :Ti ratios were prepared. Typically, the sintered ZrO 2 /Ti compacts with a porosity ranging from 78% to 82% and a bimodal pore-size distribution (0.01–0.3 and 20–90 μm, respectively) were obtained. Their pore structure, phase distribution, and mechanical strength were determined by mercury porosimetry, electron microscopy, electron probe micro-analyzer, and three-point bend test, respectively.
Databáze: OpenAIRE
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