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Test Cell

IP.com Disclosure Number: IPCOM000048565D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Sambucetti, CJ: AUTHOR [+2]

Abstract

Shown above is a simple device or dry cell that allows one to test a sample while it is being exposed to a controlled environment. The sample is first chemically treated and dried outside the cell. It is then placed in the cell and made active electrically by exposing it to relative humidity (RH) environment. Another purpose of this cell is to predict the electrical behavior of materials as a function of time of exposure to given voltages, temperatures, time and humidity levels.

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Test Cell

Shown above is a simple device or dry cell that allows one to test a sample while it is being exposed to a controlled environment. The sample is first chemically treated and dried outside the cell. It is then placed in the cell and made active electrically by exposing it to relative humidity (RH) environment. Another purpose of this cell is to predict the electrical behavior of materials as a function of time of exposure to given voltages, temperatures, time and humidity levels.

This cell provides great flexibility. Several cells can be operated with similar samples treated under different chemical conditions, so as to be able to predict the mechanism of the insulation resistance breakdown (i.e., shorts).

The cell consists of an electrochemical solid-state device or cell which is kept initially in a passive, dried condition.

The device is made of two opposing metal elements (or electrodes) 10 and 11 arranged in the configuration and geometry shown above.

A material 12, whose insulation resistance is to be determined, is first chemically treated and dried outside of the cell. The nature of the chemical treatment is to impregnate the material with electrolytes similar to the one the actual sample would encounter during fabrication and processing. The dried material is placed in the cell between the electrodes.

The device has an entry port 15 for communication to the outside where any number of ambient or humidity conditions can be applied to the cell. An exit port 16 is also available to allow the connection in series and the simultaneous operation of similar devices containing either different materials or the same materials with varying chemical treatments. In this way, a number of chemical mechanisms can be observed and determined in the same infrared (IR) run.

ln the situation where the sample (e.g., a printed circuit board) is made of copper, the positive electrode of the cell (anode) is made very large. The major reaction at copper anodes is always dissolution; hence, making the anode large prevents deterioration of the cell. On the other hand, the cathode (negative electrode) is made at least 10 times smaller to concentrate the electrical field energy in a punctual distribution on the cathode so as to achieve fast acceleration effects.

The sample is pressed tightly between the electrodes. The sample can be any kind of specimen. For example, in the case of printed circuit boards it can be a given thickness of epoxy laminate, layers of glass cloth, a slice cut of a piece of a board, or glass fibers, etc. The chemistry of the system is controller by tre...