Topseal 693 Silver Anti-Tarnish

July 21, 2022
Topseal 693 from Uyemura is free from CFCs, CHCs, HCs, chromium, and thiols.

Topseal 693 is a silver anti-tarnish conversion coating. The high-performance inorganic sealant withstands high heat and high voltages without compromise of resistivity. Contact resistance is low: <10 m W with contact force >5 cN. The thin, invisible layer of Topseal 693 does not affect surface energy or the reactivity of pure silver. 


Topseal 693 is an aqueous immersion process that is compatible with both rack and barrel application. It is free from CFCs, CHCs, HCs, chromium, and thiols. It is non-foaming, and suitable for high-speed processing. Ideal applications include connectors used in charging systems, large buses, and technical components such as contacts.

Parts treated with Topseal 693 maintain their original brightness and color.  They are also bondable, with good adhesion characteristics. The inherent high solderability of silver is fully retained.

  • Aqueous immersion process
  • Free from CFCs, CHCs, HCs, and chromium
  • Thiol-free
  • Suitable for high-speed processes
  • Non-foaming
  • Ideal for technical components such as contacts
  • High temperature resistance
  • Low contact resistance
  • Good adhesion characteristics