Chemical solution for polishing Niobium by Electrolytic Polishing Plasma

An aqueous solution of fluorinated salts specifically for plasma electropolishing of niobium and its alloys, which enables effective polishing by reducing process times and the use of hazardous chemicals compared to the conventional chemical and electrochemical polishing techniques.

How does it work?

The patent concerns a specific solution for the plasma electropolishing of niobium and its alloys, and a specific set of process parameters. Plasma electrolytic polishing, unlike standard electropolishing, works in a different regime, at higher currents and potentials. The main advantages are the polishing speed and the use of highly diluted aqueous solutions of salts and therefore less harmful to the environment and dangerous for the operator than those of the standard electropolishing that normally require concentrated acids.

The invention allows a homogeneous polishing of Niobium and its alloys via plasma electrolytic polishing with better results than those of traditional electropolishing and significantly reduced process times. Roughness values of Ra<100 nm can be achieved with this technique
The patented solution is based on ammonium fluoride (NH4F) and sodium fluoride (NaF).

Applications

• Resonant cavity polishing for accelerators and quantum computers;
• Niobium jewellery;
• Polishing of aerospace components;
• biomedical industry

Advantages

• A greener and safer chemical composition, free of toxic and highly hazardous concentrated acids that are complex to dispose of.
• Process speeds approximately 10 times faster than with the conventional methods (erosion rate of about 3.5 µm/min).
• More effective smoothing effect. More effective smoothing effect. The smoothing effect already occurs at minimum thicknesses of material removed. For the same amount of material removed, a reduction in roughness Ra approximately 2 times higher than with the classic chemical and electrochemical Nb polishing treatments.