Synthesis of crystallographically oriented olivine

Authors: Sanae Koizumi Tohru S Suzuki Yoshio Sakka Kosuke Yabe Takehiko Hiraga

Publish Date: 2016/07/09

Volume: 43, Issue: 10, Pages: 689-706

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Abstract

This study develops a fabrication technique to obtain Fefree and Febearing FeMg = 19 olivine aggregates not only with high density and fine grain size but with crystallographic preferred orientation CPO A magnetic field ≤12 T is applied to synthetic finegrained ~120 nm olivine particles dispersed in solvent The alignment of certain crystallographic axes of the particles with respect to a magnetic direction is anticipated due to magnetic anisotropy of olivine The dispersed particles are gradually consolidated on a porous alumina mold covered with a solid–liquid separation filter during drainage of the solvent The resultant aligned consolidated aggregate is then isostatically pressed and vacuum sintered We find that 1 preparation of fully reacted olivine particles with less propensity to coalesce 2 preparation of a suspension with highly dispersed particles and 3 application of a certain strength of the magnetic field are essential to obtain wellsintered and wellaligned aggregates High density ie 1 vol porosity and fine grain size ~1 μm Fefree and Febearing olivine aggregates were successfully synthesized with uniaxially aligned a and caxes respectively Attempts to uniaxially align the magnetization hard axis and to triaxially align Febearing olivine by rotating the suspension in the magnetic field succeeded in obtaining weakly developed CPO aggregatesWe thank Ube Materials S Ohtsuka T Moroyama M Uchida N Hokanishi A Takeuchi and A Yasuda for their technical assistances A portion of this work was conducted at the Center for Nano Lithography and Analysis of the University of Tokyo supported by the Ministry of Education Culture Sports Science and Technology MEXT Japan This study was supported by the JSPS through GrantinAid for Scientific Research 26247087 26610170 and 15H05827 and Earthquake Research Institute’s cooperative research program to TH

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