Protecting Copper Parts Coated With Silver.

Background: Xidan-Mitsubishi would like long-term protection for silver coated copper parts.

Purpose: To determine the protection provided to silver coated copper parts with EcoClean Silver and Gold Cleaner and VpCI™-238.

Materials: EcoClean Silver and Gold Cleaner


Method: Humidity Chamber

Procedure: 4 parts were received from Xidan-Mitsubishi. The parts arrived heavily tarnished; it was not feasible to remove all of the tarnish from the parts. After an hour of cleaning, 75% of the tarnish had been removed. One set of parts was coated with VpCI™-238 and they were placed in the Humidity Chamber. The parts were periodically checked, they were removed after 10 days, pictures were taken and a report was written.

Results: After 4 days th Control (untreated parts) showed minor tarnishing, and it was 10 days before the treated parts showed minor tarnishing:


Time in Chamber (days)

Amount of Tarnishing

(only on area that was prepped)

VpCI™-238 and

EcoClean Cleaner


5% of the surface

EcoClean Cleaner


15% of the surface



15% of the surface

Conclusion: EcoClean Silver and Gold Cleaner alone lasted 2.5 times longer than the Control before tarnishing appeared on 15% of the surface. VpCI™-238 in combination with EcoClean Silver and Gold Cleaner provided very good protection to the silver coated copper parts. An initial cleaning with EcoClean Silver and Gold Cleaner maintenance schedule with the reapplication of VpCI™-238 should keep the parts corrosion free for the long term.

Project #: 01-258-1725

Time Spent on Project: 3.0 hours

To: Steven Xu, Itochu International Inc.

For: Xidan-Mitsubishi, Xidan China

From: Brian L. Wuertz

Date: 11-9-2001

cc: Boris Miksic

Anna Vignetti

Art Ahlbrecht

Margarita Kharshan

Cliff Cracauer

Vanessa Schultz

Christophe Chandler