Technical PM Surface Protection
Topseal 693 Silver Anti-tarnish is a thin, invisible inorganic conversion coating. It is an aqueous immersion process that is free from CFCs, CHCs, HCs, chromium and thiols. The product is non-foaming and suitable for high-speed processing.
Topseal 693 withstands high heat and high voltages without compromise of resistivity. Contact resistance is low: <10 m W with contact force >5 cN.
Treated parts are solderable and bondable, and provide good adhesion. This advanced process is proven on connectors used in charging systems, large buses and technical components such as contacts. It is compatible with both rack and barrel application.
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Sealing 691 and 692 provide long-term protection for yellow and rose gold, silver, copper and tin. Sealing 691 and 692 permanently preserve metal brightness and luster on high-end jewelry, handles, rivets and other decorative metal components. They also seal thin gold’s inherent porosity more effectively than alternatives.
Engineered nanopolymers penetrate the grain structure, preventing oxidation of the underlying nickel or copper, so when gold is applied, plated parts exhibit high levels of corrosion resistance.
Often, a deposit a few nanometers thick is specified; the addition of current allows the building of a layer many molecules thick where desirable.
The 691/692 organic molecule has a unique affinity for electrodeposition – and unrivaled process flexibility. Both processes have a dwell time as short as 4 seconds, compared to competitive products at 30 seconds or longer.
Gold alone often fails to meet a high corrosion specification; Sealing 691 and 692 allow products to easily meet these standards.
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, barrel and reel-to-reel equipment.
Sealing 691 with Basic Additive enhances anti-tarnish protection. It also reduces the friction coefficient, making it suitable for sliding and plug-in contacts, as well as decorative applications; it has no adverse effects on solderability or contact resistance.
Sealing 616 protects silver against tarnishing; it is well suited for FDA applications.
Sealing 691 and 692, and Topseal 693, were developed by Umicore Galvanotechnik. They are available throughout North America exclusively from Uyemura. For more details, or to arrange test processing, email us or contact your Uyemura representative.