Sintering mechanisms and dielectric properties of cold sintered (1-x) SiO2 - x PTFE composites

Arnaud Ndayishimiye, Kosuke Tsuji, Ke Wang, Sun Hwi Bang, Clive A. Randall

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Abstract

This study reports the sintering mechanisms of SiO2 and the relationship between structure, dielectric properties and processing of 1-xSiO2-xPTFE composites with volume fractions up to x = 0.25, prepared by the cold sintering process (270 °C, 430 MPa, 60 min). The importance of transient liquids was evaluated by using TEOS and 5 M NaOH and the densification behavior was investigated by using a semiautomated uniaxial press equipped with a dilatometer. The shrinkage behavior observed when 5 M NaOH was used highlighted the kinetics of nucleation and growth during the phase transition from amorphous silica to α-quartz. Dielectric properties (ε’ and tan δ) of cold sintered composites were studied at frequencies between 10−1 Hz and 107 Hz. For composites cold sintered with 5 M NaOH, investigations allowed to confirm the presence of PTFE polymer at the interface between two α-quartz grains by STEM EDS analysis and the presence of a dielectric relaxation at 103-104 Hz.

Original languageEnglish (US)
Pages (from-to)4743-4751
Number of pages9
JournalJournal of the European Ceramic Society
Volume39
Issue number15
DOIs
StatePublished - Dec 2019

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All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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