Microstructural Control of Colloidal‐Based Ceramics by Directional Solidification Under Weak Magnetic Fields. Issue 6 (14th March 2016)

• Record Type: Journal Article
• Authors: Porter, Michael M.; Niksiar, Pooya; McKittrick, Joanna
• Editors: Franks, G.
• Is Part Of: Journal of the American Ceramic Society. Volume 99:Issue 6(2016)
• Page Start: 1917
• Page End: 1926
• Publication Date: 2016-03-14
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.14183
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract : The use of weak magnetic fields to control the microstructural evolution of colloidal‐based systems in conjunction with directional solidification is demonstrated as a convenient processing route to fabricate anisotropic ceramic scaffolds with complex microarchitectures. A variety of graded and aligned microstructures were formed by applying external static magnetic fields oriented radially, axially, and transversely with respect to the solidification direction of freezing slurries containing micro/nanoparticles of ZrO2 and Fe3 O4 . The graded structures, formed by the radial and axial fields, resemble core–shell architectures composed of dense outer perimeters surrounding porous inner cores. The aligned structures, formed by transverse fields, exhibit two modes of microstructural alignment: lamellar walls aligned by the growing ice crystals and mineral bridges aligned by the magnetic fields. The alignment of mineral bridges that connect adjacent lamellae, provide these scaffolds enhanced strength and stiffness when compressed parallel to their orientation (parallel to the direction of the magnetic field).