Wayne Herndon Rare Coins, Inc. :: Intercept Shield Technology
|Intercept Shield Technology
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, click on the
"Products" link above.
Abstract (to view this report in it's entirety,
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.
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.
Five types of storage boxes were evaluated:
Intercept Album, multipage book with clear plastic covered
slot and an outer cover with Intercept Technology throughout the book.
Sample X Album, similar to 1, different vendor, no Intercept
Sample Y Album, similar to 1, different vendor, no Intercept
Intercept Tri Fold, open coin slots: cover folds onto itself.
Intercept Technology protected
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.
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.