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Title: Enhanced dielectric standoff and mechanical failure in field-structured composites

Abstract

We report dielectric breakdown experiments on electric-field-structured composites of high-dielectric-constant BaTiO{sub 3} particles in an epoxy resin. These experiments show a significant increase in the dielectric standoff strength perpendicular to the field structuring direction, relative to control samples consisting of randomly dispersed particles. To understand the relation of this observation to microstructure, we apply a simple {ital resistor-short breakdown model} to three-dimensional composite structures generated from a dynamical simulation. In this breakdown model the composite material is assumed to conduct primarily through particle contacts, so the simulated structures are mapped onto a resistor network where the center of mass of each particle is a node that is connected to neighboring nodes by resistors of fixed resistance that irreversibly short to perfect conductors when the current reaches a threshold value. This model gives relative breakdown voltages that are in good agreement with experimental results. Finally, we consider a primitive model of the mechanical strength of a field-structured composite material, which is a current-driven, {ital conductor-insulator fuse model}. This model leads to a macroscopic fusing behavior and can be related to mechanical failure of the composite. {copyright} {ital 1999} {ital The American Physical Society}

Authors:
; ; ;  [1]
  1. Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)
Publication Date:
OSTI Identifier:
686448
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 60; Journal Issue: 10; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BARIUM COMPOUNDS; FERROELECTRIC MATERIALS; FAILURES; RESINS; BARIUM OXIDES; TITANIUM OXIDES; DIELECTRIC PROPERTIES; DIELECTRIC TENSOR; PERMITTIVITY; BREAKDOWN; FLEXURAL STRENGTH; COMPOSITE MATERIALS

Citation Formats

Martin, J.E., Tigges, C.P., Anderson, R.A., and Odinek, J. Enhanced dielectric standoff and mechanical failure in field-structured composites. United States: N. p., 1999. Web. doi:10.1103/PhysRevB.60.7127.
Martin, J.E., Tigges, C.P., Anderson, R.A., & Odinek, J. Enhanced dielectric standoff and mechanical failure in field-structured composites. United States. doi:10.1103/PhysRevB.60.7127.
Martin, J.E., Tigges, C.P., Anderson, R.A., and Odinek, J. Wed . "Enhanced dielectric standoff and mechanical failure in field-structured composites". United States. doi:10.1103/PhysRevB.60.7127.
@article{osti_686448,
title = {Enhanced dielectric standoff and mechanical failure in field-structured composites},
author = {Martin, J.E. and Tigges, C.P. and Anderson, R.A. and Odinek, J.},
abstractNote = {We report dielectric breakdown experiments on electric-field-structured composites of high-dielectric-constant BaTiO{sub 3} particles in an epoxy resin. These experiments show a significant increase in the dielectric standoff strength perpendicular to the field structuring direction, relative to control samples consisting of randomly dispersed particles. To understand the relation of this observation to microstructure, we apply a simple {ital resistor-short breakdown model} to three-dimensional composite structures generated from a dynamical simulation. In this breakdown model the composite material is assumed to conduct primarily through particle contacts, so the simulated structures are mapped onto a resistor network where the center of mass of each particle is a node that is connected to neighboring nodes by resistors of fixed resistance that irreversibly short to perfect conductors when the current reaches a threshold value. This model gives relative breakdown voltages that are in good agreement with experimental results. Finally, we consider a primitive model of the mechanical strength of a field-structured composite material, which is a current-driven, {ital conductor-insulator fuse model}. This model leads to a macroscopic fusing behavior and can be related to mechanical failure of the composite. {copyright} {ital 1999} {ital The American Physical Society}},
doi = {10.1103/PhysRevB.60.7127},
journal = {Physical Review, B: Condensed Matter},
number = 10,
volume = 60,
place = {United States},
year = {1999},
month = {9}
}