ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY METHOD AND SYSTEM
First Claim
1. An apparatus for measuring impedance of a coating on a substrate comprising:
- a first cell chamber;
wherein said first cell chamber has a first opening;
a counter-reference electrode positioned in said first cell chamber;
a second cell chamber;
wherein said second cell chamber has a second opening;
a working electrode positioned in said second cell chamber;
an electrolyte positioned in said first, second cell chambers;
wherein said electrolyte is in electrical contact with said counter-reference electrode in said first cell chamber;
wherein said electrolyte is in electrical contact with said working electrode in said second cell chamber;
means for securing said first opening and said second opening to a coating;
wherein said electrolyte makes electrical contact with said coating when said first opening and said second opening are in contact with said coating by said means for securing;
a potentiostat electrically connected to said counter-reference electrode and to said working electrode;
wherein said potentiostat is adapted to apply alternating voltage at varying frequencies to said working electrode and measure current at said counter-reference electrode;
means for calculating impedance from measured current; and
means for outputting impedance.
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Accused Products
Abstract
A dual cell Electrochemical Impedance System (EIS) testing apparatus and method for measuring coating integrity on various substrates. The counter reference electrode is in a first cell in electrical contact with the coating. The working electrode is in a second cell in electrical contact with the coating instead of the substrate material acting as the working electrode. Voltage is applied at the working electrode at varying frequencies and current is measured at the combined reference/counter electrode. From the known voltage and the measured current, the impedance of the coating is calculated. Coatings on non-metallic substrates can be measured with this apparatus. In one embodiment, the EIS cells are in the form of vacuum cups containing an electrolyte gel for testing non-horizontal coatings in the field. Also, known current can be applied to the working electrode and voltage measured at the counter reference electrode can be used to calculate coating impedance.
22 Citations
27 Claims
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1. An apparatus for measuring impedance of a coating on a substrate comprising:
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a first cell chamber; wherein said first cell chamber has a first opening; a counter-reference electrode positioned in said first cell chamber; a second cell chamber; wherein said second cell chamber has a second opening; a working electrode positioned in said second cell chamber; an electrolyte positioned in said first, second cell chambers; wherein said electrolyte is in electrical contact with said counter-reference electrode in said first cell chamber; wherein said electrolyte is in electrical contact with said working electrode in said second cell chamber; means for securing said first opening and said second opening to a coating; wherein said electrolyte makes electrical contact with said coating when said first opening and said second opening are in contact with said coating by said means for securing; a potentiostat electrically connected to said counter-reference electrode and to said working electrode; wherein said potentiostat is adapted to apply alternating voltage at varying frequencies to said working electrode and measure current at said counter-reference electrode; means for calculating impedance from measured current; and means for outputting impedance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for measuring the impedance of a coating on a substrate comprising:
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a first vacuum cup having a first cavity; a counter-reference electrode positioned in said first cavity; a second vacuum cup having a second cavity; a working electrode positioned in said second cavity; an electrolyte positioned in said first, second cavities; said electrolyte adapted to conduct electricity between a coating and an electrode; a potentiostat electrically connected to said counter-reference electrode and said working electrode; wherein said potentiostat is adapted to apply alternating current at varying frequencies to said working electrode and measure potential at said counter-reference electrode; means for calculating impedance from measured potential; and means for outputting impedance. - View Dependent Claims (14, 15, 16)
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17. An electrode cell for measuring impedance of a coating on a substrate comprising:
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a planar vacuum cup base having a first aperture; a resilient vacuum pad having first and second sides, said first side adapted to mate with said planar vacuum cup base; said second side of said vacuum pad having a concave cavity; a second aperture in said vacuum pad adapted to align with said first aperture; an electrode comprising a disk and perpendicular stem; said disk of said electrode adapted to fit inside said concave cavity of said vacuum pad; said stem of said electrode adapted to fit in said first aperture and said second aperture; wherein said stem is further adapted to couple said vacuum pad to said vacuum base; said stem adapted to electrically connect to a potentiostat; an electrolyte positioned in said concave cavity; said electrolyte adapted to conduct electricity between a coating and said electrode; wherein when said concave cavity of said vacuum pad containing said electrolyte is positioned on a coating, said electrode makes electrical contact with the coating through said electrolyte. - View Dependent Claims (18, 19, 20)
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21. A method for measuring impedance of a coating on a substrate comprising:
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providing a first electrode chamber having a counter-reference electrode and an electrolyte in said chamber; providing a second electrode chamber having a working electrode and an electrolyte in said chamber; providing a potentiostat adapted to apply alternating voltage at varying frequencies to said working electrode and measure current at said counter-reference electrode; coupling said first and second electrode chamber to a coating wherein said electrolyte makes electrical contact with said coating; applying alternating voltage at varying frequencies to said working electrode; measuring current at said counter-reference electrode; calculating impedance from said measured current; and outputting impedance to interpret coating integrity. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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Specification