Device for Conductivity Measurement in a Controlled Environment and Method Thereof

KSU-333

Abstract: The conductivity of powders is usually measured using AC impedance after compressing powder into a pellet and depositing or pressing electrodes against it; but this design does not allow for quick equilibration of water content in the sample and surrounding area.  It also complicates analysis of the sample's impedance spectra, due to presence of two interfacial impedances.  A more recent design reported uses a conductivity cell, allowing for measurements on a loose powder placed into a cylindrical hole and squeezed between two rod electrodes under variable load pressure, but it does not resolve the problems of interfacial impedance and water equilibration.  Our development provides a device and method for measuring the conductivity in a controlled environment.  In simplest terms, this invention consists of a method employing a device consisting of a box with holes drilled in polyetherimide with the powder put into a cylindrical channel;  electrodes inserted at the ends with constant pressure; and with platinum wires inserted in holes pendicularly intersecting the large channel and penetrating the entire width.

Applications: To measure conductivity of powder samples at various temperatures and relative humidities

Advantages:

•          Provides greater efficiency
•          Resolves problem of interfacial impedance
•          Resolves problem of maintaining constant inter-electrode distance
•          Resolves problem of humidity equilibration
•          Resolves problem of loss of contact between sample and electrode upon sample shrinking
•          Utilizes a simple, low-cost design

Inventors: Dr. Yuriy Tolmachev and Evgeny Garanin