AURUNA® 3408 Cyanide-free Gold Copper Electrolyte

Cyanide-Free Gold-Copper Plating Solution with Exceptional Purity

AURUNA® 3408 is a cyanide-free Gold-Copper plating solution featuring an extremely high-purity gold deposit containing approximately 99.7% pure gold. Despite its high purity, the coating still delivers impressive mechanical stability, with hardness up to 180 HV according to the Vickers method. Thanks to its low internal stress, the coating can achieve thicknesses up to 10 μm without cracking or peeling. The deposit is bright with a pale yellow color, making it ideal for refined, high-end decorative surfaces. Excellent corrosion resistance ensures long-term performance in functional technical applications even under demanding conditions.

AURUNA® 3408 contains no problematic grain refiners such as arsenic, thallium, lead, cadmium, cobalt, or tellurium. This makes the solution not only non-toxic but also suitable for unrestricted worldwide use — a clear advantage for environmentally friendly manufacturing processes. In addition, the solution can be replenished without complete replacement, helping save raw materials.

The plating process can be flexibly carried out using either rack or barrel methods, expanding its range of applications — the solution can even be used in printed circuit board production. AURUNA® 3408 combines maximum material purity, technical performance, and environmental friendliness in a single product — an advanced solution for modern surface technology.

Bath Characteristics

• Bath type: Neutral.
• Metal content: 5 (4 – 6) g/l Gold, 15 (10 – 20) mg/l Copper.
• pH value: 8.2 (8.0 – 8.4).
• Operating temperature: 65 (60 – 70) °C.
• Current density range: 0.3 (0.1 – 0.5) A/dm².
• Deposition rate: Approx. 0.18 μm/min at 0.3 A/dm².
• Deposition amount: Approx. 116 mg/Am min at 0.3 A/dm².

Coating Characteristics

• Coating: Gold-Copper alloy.
• Purity: Approx. 99.7 wt.% Gold, approx. 0.3 wt.% Copper.
• Deposit color: Pale yellow.
• Hardness: Approx. 180 HV.
• Maximum coating thickness: Approx. 10 μm.
• Density: Approx. 19 g/cm³.

Features

• Cyanide-free gold-copper electrolyte
• Extremely high pure gold content (approx. 99.7%)
• Excellent mechanical stability
• Low internal stress
• Crack-free coatings up to 10 μm thickness
• Bright pale yellow deposits
• Excellent corrosion resistance
• Non-toxic and therefore suitable for unrestricted worldwide use
• Suitable for rack or barrel operation

Applications

• Jewelry
• Eyewear frames
• Watches
• Printed circuit boards
• Connectors