Anodizing is a simple and fun way to add color to your niobium work. What, you don’t work in niobium?? Why not? Niobium is hypoallergenic and naturally silver-gray with an extraordinary capacity to take on color using nothing more than a micro anodizer and a cup of electrolyte.
Unlike silver and other metals we are more accustomed to working with (where color is physically applied through enamels, resins, pastes, e-coating etc.), niobium forms an oxide layer on its surface that translates as a color that can be controlled. No color added. These colors cover the entire spectrum of the rainbow and can be very bright. Working with this material does pose a few challenges but it offers such a large—and colorful—reward for your effort.
Niobium is very malleable and can be formed and manipulated easily. Although soft and easy to shape, it will hold its form. Niobium can easily be rolled in a rolling mill with pattern plates, manipulated in a Bonny Doon hydraulic press, or simply forged with a hammer from flat stock. Niobium cannot be soldered and needs to be welded. Cold connections are typically the easiest way to connect this metal to itself and other materials.
When I created the niobium bracelet above, I wanted to control the color and use very subtle forming techniques. The pieces were cut out using a bench shear, then hand shaped and filed. When you’re working with niobium it is important to use separate finishing tools such as files, sandpapers and buffs. Particles from silver and other metals transferred from tools can become embedded into the surface of the niobium, causing those areas not to anodize. After cutting and filing my shapes I used the Durston Cupolas, one of my favorite dapping tools, to provide a nice shallow curve to the pieces. Once the pieces were shaped the way I imagined, I laid them out and cut holes into them using the riveting system. Then I smoothed the edges and holes with radial bristle discs on a polishing motor.
Anodizing or coloring niobium is usually the last step when working with the material. In order to anodize you will need the following:
- SMT Micro Anodizer
- Phosphate-Free Trisodium Phosphate Electrolyte Granules
- a container for your solution
Before anodizing you will need to finish the piece by either polishing or texturing the metal. Coarse Scotch-Brite works great on niobium. Sanding in different directions, or having both polished and textured areas on a piece of niobium allows the colors to reflect differently, appearing to turn off and on as the angle of the light changes.
Now it’s time to anodize. Before anodizing, it’s very helpful to consult a color chart. Each voltage gives the niobium a specific color; by having a chart on hand, you can plan which colors you want to use on your piece. One typically anodizes the metal after forming it; however, sometimes anodizing a piece of sheet metal before forming can result in some very unique color combinations. In the following video Bill Seeley gives a great demonstration of how to anodize reactive metals:
Niobium is an awesome hypoallergenic, tarnish-resistant, lustrous gray metal that can be transformed easily and anodized in brilliant colors. Give Rio Grande a call today and see how anodized niobium can benefit your work! Want to learn more about this unique process? Visit Rio’s articles and videos page for more information. Also, be sure to check out Rio’s Niobium & Titanium Jewelry board on Pinterest for more inspiring examples of this technique!