The Proof

In comparison tests with other methods of corrosion protection, Intercept Shield ™ is clearly the most effective of all those available today. Lucent Technologies tested three different coin albums the results of which, are shown below. This remarkable technology provides 10 years of corrosion protection for each thousandth of an inch thickness, under normally encountered corrosive conditions. To get Intercept Shield ™ products, go to your local coin dealer.

Abstract (to view this report in it's entirety,
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Subject: Performance analysis of the corrosion protection of Intercept Technology ® licensed metal substrate storage product

Intercept Technology ® is a Lucent Technologies patented and licensed polymer process. The Technology has been licensed, manufactured, distributed, and sold by our licensees since 1991. In order to ensure the highest quality production, and manufacture of Intercept products are maintained, samples of production materials are regularly retained and tested. These checks, coupled with periodic inspections and updated improvements in formulations create a technically advanced product. Periodically, final products are laboratory tested for static and/or corrosion protection performance.

Coin storage systems are designed to protect copper, silver and their alloys from tarnishing. These metals are commonplace in the electronic equipment Lucent Technologies manufactures. Therefore, it is beneficial for Lucent Technologies Bell Labs to test their performance of such systems so as to expand our information base in the matter of the atmospheric corrosion protection of electronic materials. This report describes such a test for corrosion protection and its results.

Storage systems for coinage have been tested for corrosion protection from atmospheric trace sulfur gases. Intercept Technology significantly outperformed non-Intercept Technology systems.

Background

Copper, silver and their alloys have been degraded from atmospheric gases from the moment they were purified and polished more than 5,000 years ago. The most abundant corrosive gas is oxygen.

Upon exposure to oxygen copper forms an oxide film of Cu2O, which, is semitransparent, and self limiting. This oxide grows to approximately 15Å in one hour to an upper limit of approximately 2 NM at 20° C2.

Typical copper degradation occurs when sulfur and water vapor are deposited on the metal surfaces. Liquid water, sufficient to form an acidic condensate slurry with sulfur, occurs at relative humidity levels greater than 60%. This slurry penetrates and breaks protective oxide interstitial grain boundary bonds. Eventually, sulfur and copper ions form copper sulfide, which, mix into the oxide, and form directly on the copper surfaces. In very thin layers an overall darkening will occur at thicknesses as low as 10 nm3.

Typically, experiments used to mimic these natural occurring processes utilize water and a corrosive gas. We have chosen this proven method to evaluate product performance. The gas we wish to use as a catalyst for the test is hydrogen sulfide. It is abundant in the atmosphere. It has a natural vapor pressure of 292 psi at STP, is colorless, and it has an affinity for reacting with copper having a chemical stoichiometry favoring a Cu reaction as does carbonyl sulfide and three to four times more than So2.

Experimental

Five types of storage boxes were evaluated:

1. Intercept Album, multipage book with clear plastic covered slot and an outer cover with Intercept Technology throughout the book.
2. Sample X Album, similar to 1, different vendor, no Intercept
3. Sample Y Album, similar to 1, different vendor, no Intercept
4. Intercept Tri Fold, open coin slots: cover folds onto itself. Intercept Technology protected
5. Sample Z Tri Fold, open coin slots: cover folds onto itself. No Intercept Technology

The populated books were placed in the test chamber for a 150ppm hour exposure. Previous work indicated this exposure is equivalent to average ambient H2S exposure for 10 years.

Results

Summary

The evaluation of Intercept Technology ® encompassed equivalent 10 year sulfurous atmospheric trace gas corrosion testing followed by optical evaluation, scanning electron microscopy, and x-ray elemental analysis. This generic testing and evaluation was designed to demonstrate the protection ability of material packages in reference to corrosive atmospheric sulfur trace gases and their reactions with copper, silver, and their alloys. The test results show the tested Intercept Shield ™ products offer a considerable increase over other non-Intercept protective products.