Etching niobium with Multi-Etch

Niobium in various forms. By Multi-Etch, LLC.

Niobium in various forms. By Multi-Etch, LLC.

How to etch niobium with Multi-Etch, the safer alternative to hydrofluoric acid

Multi-Etch was originally developed for use on titanium, and is a perfect low-acid (pH 6.8) alternative to hazardous hydrofluoric (HF) acid for etching niobium

Preparing niobium for anodizing using Multi‑Etch

Not usually necessary. Sometimes niobium arrives with mill oxides which are hard to see and may require etching to get good color. For many small parts, use a tumbler with ceramic media moistened with double strength Multi-Etch; tumble for approximately 15 minutes.

Removing color from niobium using Multi‑Etch
Note: times are for removing high-voltage green completely; lower voltage colors will take less time to remove.
Process Etch time Surface change
150–160°F regular strength 4.5 minutes No change
150–160°F double strength 3.5 minutes Slightly matte
70°F regular strength Not practical
Etch rates for niobium using Multi‑Etch
Process Etch time (minutes) Etch depth (inches, cumulative total) Surface change
150–160°F double strength
1 0.00006 Trending toward matte
2 0.00015 Matte
3 0.00023 Matte
Removing a drill bit from niobium using Multi‑Etch
Note: 3 minutes will remove enough to be picked out; etch longer to dissolve whole bit.
Process Etch time (minutes) Surface change
135°F regular strength 3+ Trend toward matte
Preparing niobium for electron beam welding using Multi‑Etch
Process Etch time (minutes) Surface change
135°F double strength 1 Polish will turn slightly matte

Step-by-step guides on etching with Multi-Etch

The guides below demonstrate etching with titanium, but the order of steps are the same for etching niobium.

Tips and tricks when etching with Multi-Etch

Ordering Multi-Etch

Multi-Etch can be ordered throughout the world! View the list of Multi-Etch retailers.

Questions? You can contact Multi-Etch by phone or email.