Organic Nanotechnology Process Preserves Metal Brightness Indefinitely, Allows Reductions in Precious Metal Use

Short dwell time is ideal for reel-to-reel

Manufacturers of leather goods, jewelry, hardware and other consumer goods seek long-term protection for precious metal components: a treatment that is invisible, yet prevents oxidation and discoloration over a long service life.

They also seek to limit the consumption of precious metals. With both objectives, the challenge is to do so without detracting from product appearance, feel and overall value perception.

Sealing 691 protects yellow and rose gold, silver, copper and tin. Its proprietary organic molecule has a unique affinity for electrodeposition – and unrivaled process flexibility. It has a short dwell time – as little as 4 seconds, compared to competitive products at approximately 30 seconds – and is ideally suited to reel-to-reel processing.

Sealing 691 permanently preserves metal brightness and luster on high-end jewelry, handles, rivets and other decorative metal components. It also seals thin gold's inherent porosity more effectively than alternatives.

Engineered nanopolymers absorb on the metal surface, crosslinking to form an invisible, undetectable layer. By penetrating the grain structure, it prevents oxidation of the underlying nickel or copper, so when gold is applied, plated parts exhibit high levels of corrosion resistance.

And while a layer of protection a few nanometers thick is what’s most often specified, the use of current allows the building of a layer many molecules thick where desirable.

Global consumer goods manufacturers find that gold alone often fails to meet a high corrosion specification; Sealing 691 allows product to easily meet these standards.

Other features include:

  • aqueous formula
  • chrome-free
  • RoHS compliant
  • hypoallergenic
  • stain repellent
  • preserves solderability and bonding capacity
  • low contact resistance

Sealing 691 preserves metal's inherent lubricity and leaves technical characteristics unaffected, so it has substantial advantages for electronic applications such as plug connectors. It can be used in rack or barrel equipment, and is particularly well-suited to reel-to-reel equipment.

Sealing 691 was developed by Umicore Galvanotechnik as an improved version of its popular Antitarnish 616 PLUS. It is available throughout North America exclusively from Uyemura.

Also available: Sealing 691 EL (electrolytic process)

Sealing 691 EL protects technical precious metal surfaces, including electrical contacts. Advantages include reduced coefficient of friction, improved sliding performance for connectors and and long-term protection of the functional layer, even under high mechanical stress. In addition, electrical characteristics, solderability and contact resistance are all unaffected.

Silver surfaces treated with Sealing 691 EL as a final layer produce outstanding results in K2S tests. Sealing 691 EL was developed for electrolytic application in continuous lines and has a very short contact time.

For more details, or to arrange test processing, contact your Uyemura representative.