Synergistic structures from magnetic freeze casting with surface magnetized alumina particles and platelets

Michael B Frank; Sze Hei Siu; Keyur Karandikar; Chin-Hung Liu; Steven E Naleway; Michael M Porter; Olivia A Graeve; Joanna McKittrick

doi:10.1016/j.jmbbm.2017.06.002

Synergistic structures from magnetic freeze casting with surface magnetized alumina particles and platelets

J Mech Behav Biomed Mater. 2017 Dec:76:153-163. doi: 10.1016/j.jmbbm.2017.06.002. Epub 2017 Jun 3.

Authors

Michael B Frank¹, Sze Hei Siu², Keyur Karandikar³, Chin-Hung Liu³, Steven E Naleway⁴, Michael M Porter⁵, Olivia A Graeve⁶, Joanna McKittrick⁶

Affiliations

¹ Materials Science and Engineering Program, USA. Electronic address: mbfrank@ucsd.edu.
² Department of Mechanical and Aerospace Engineering University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
³ Materials Science and Engineering Program, USA.
⁴ Department of Mechanical Engineering University of Utah, 1495 E 100 S, Salt Lake City, UT 84112, USA.
⁵ Department of Mechanical Engineering Clemson University, Clemson, SC 29634, USA.
⁶ Materials Science and Engineering Program, USA; Department of Mechanical and Aerospace Engineering University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.

PMID: 28622962
DOI: 10.1016/j.jmbbm.2017.06.002

Abstract

Magnetic freeze casting utilizes the freezing of water, a low magnetic field and surface magnetized materials to make multi-axis strengthened porous scaffolds. A much greater magnetic moment was measured for larger magnetized alumina platelets compared with smaller particles, which indicated that more platelet aggregation occurred within slurries. This led to more lamellar wall alignment along the magnetic field direction during magnetic freeze casting at 75 mT. Slurries with varying ratios of magnetized particles to platelets (0:1, 1:3, 1:1, 3:1, 7:1, 1:0) produced porous scaffolds with different structural features and degrees of lamellar wall alignment. The greatest mechanical enhancement in the magnetic field direction was identified in the synergistic condition with the highest particle to platelet ratio (7:1). Magnetic freeze casting with varying ratios of magnetized anisotropic and isotropic alumina provided insights about how heterogeneous morphologies aggregate within lamellar walls that impact mechanical properties. Fabrication of strengthened scaffolds with multi-axis aligned porosity was achieved without introducing different solid materials, freezing agents or additives. Resemblance of 7:1 particle to platelet scaffold microstructure to wood light-frame house construction is framed in the context of assembly inspiration being derived from both natural and synthetic sources.

Keywords: Ceramic scaffold; Ferrofluid; Freeze casting; Magnetic alignment; Mechanical properties; Particles; Platelets.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Aluminum Oxide / chemistry*
Freezing*
Magnetic Fields*
Mechanical Phenomena
Surface Properties

Substances

Aluminum Oxide