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Nanocomposite Derived from Core–Shell Nanoparticles via Creep Deformation of an Amorphous Silica Layer Below its Glass Transition Temperature
Author(s) -
Kinemuchi Yoshiaki,
Towata Atsuya,
Yasuoka Masaki
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12150
Subject(s) - materials science , amorphous solid , nanoparticle , ceramic , creep , composite material , nanocomposite , nanostructure , microstructure , grain growth , glass transition , sintering , layer (electronics) , deformation (meteorology) , nanotechnology , crystallography , polymer , chemistry
The microstructural design of ceramics is relevant to tune their properties. Nanostructuring can drastically modify ceramic properties because of enhanced interfacial effects, although the creation of such structures in ceramics is still challenging because of the interfacial reaction and grain growth at elevated temperatures during sintering. Here, we demonstrate densification of core – shell nanoparticles consisting of Fe 3 O 4 (core particle, 20 nm diameter) and SiO 2 (shell layer, 2 nm thick) with over 90% of theoretical density below 500°C, which was achieved by facilitating plastic flow of amorphous SiO 2 under high pressure below its glass transition temperature. Thus, grain growth of the core nanoparticles was strongly suppressed, and the core nanoparticles remained separated by an amorphous layer in the final microstructure reflecting the original core–shell nanostructure. We also analyzed the densification behavior on the basis of a power law creep model, and estimated the pressures required to attain full density.