PLATUNA® Alloy RH Platinum Rhodium Electrolyte

Wear-resistant platinum-rhodium coating for brilliant jewelry.

With the strongly acidic PLATUNA® Alloy RH alloy electrolyte, smooth, bright, and crack-free platinum-rhodium coatings can be produced with a coating thickness of up to 0.5 μm. The resulting deposits have a brilliant gloss and, unlike conventional platinum coatings, do not show a yellowish tint.

An important advantage of this coating is its high hardness thanks to the rhodium content. In addition, the electrolyte has a low sulfuric acid content, making it less corrosive to the substrate. The deposition rate is independent of current density, ensuring optimal coating thickness distribution. No precipitation occurs, and the platinum concentrate does not need to be stored in a refrigerator.

Solution characteristics
Solution type: Strongly acidic
Metal content: 1.2 (0.8 – 1.6) g/L Pt, 0.3 (0.2 – 0.4) g/L Rh
pH value: <1
Operating temperature: 60 (55 – 65) °C
Current density range: 5 (0.5 – 10) A/dm²
Plating rate: approx. 0.12 μm/min at 5 A/dm²
Deposition rate: approx. 4.7 mg/Amin at 5 A/dm²

Coating characteristics
Coating: Platinum-rhodium
Alloy composition: approx. 80% Pt, approx. 20% Rh
Deposit color: White
Brightness: Bright, metallic gloss
Hardness: not measurable, approx. 600 HV
Maximum coating thickness: approx. 0.5 μm
Coating density: approx. 18.7 g/cm³

Advantages
Wear-resistant, bright, high-gloss coating
Crack-free up to a thickness of 1 μm
High plating rate
High deposition efficiency

Applications
Jewelry
Watches
Writing instruments
Eyewear frames
Metal fittings