A three-dimensional network model describing a non-linear composite material

A three-dimensional network model for performing non-linear time-dependent simulations of the electrical characteristics related to a composite material is presented. The considered compounds are represented by a cubic lattice and consist of conducting particles distributed in an insulating matrix....

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Bibliographic Details
Published in:Journal of physics. D, Applied physics Applied physics, 2004-01, Vol.37 (1), p.112-119
Main Authors: MARTENSSON, E, GÄFVERT, U
Format: Article
Language:English
Subjects:
Applied sciences
Composite materials
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Conductivity of specific materials
Electrical, magnetic and optical properties
Electronic transport in condensed matter
Exact sciences and technology
General formulation of transport theory
Organic polymers
Physicochemistry of polymers
Physics
Properties and characterization
Theory of electronic transport
scattering mechanisms
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Summary:A three-dimensional network model for performing non-linear time-dependent simulations of the electrical characteristics related to a composite material is presented. The considered compounds are represented by a cubic lattice and consist of conducting particles distributed in an insulating matrix. Earlier studies of the non-linear characteristics of silicon carbide (SiC) grains and of the linear frequency-dependent electrical properties of composites are combined and extended. The calculations are compared to measurements on ethylene-propylene-diene monomer rubber filled with angular SiC grains. The field-dependent conductivity measured for the unconsolidated SiC powder is used as input to the simulations. The model can manage the conductivity difference of seven decades between the constituents and the strong exponential non-linearity of the conducting particles. The network calculations replicate the experimental characteristic at high filler concentrations, where direct `face' contacts between the filler grains dominate the behavior. At lower concentrations, it is shown that indirect 'edge' contacts involving the polymer control the current transport also in the non-linear high field range. The general effective conductivity describing an edge connection in the linear case is no longer appropriate. Non-linear mechanisms in the polymer and the conducting grains within a field enhanced limited region around the contact need to be represented by an equivalent circuit element with a case-dependent resulting expression.
ISSN:0022-3727
1361-6463
1361-6463
DOI:10.1088/0022-3727/37/1/019