What is Niobium?
Niobium is a metal in the periodic table (Nb) that’s durable and hypoallergenic. It’s a rare and precious material that’s lightweight and strong — perfect for jewellery!
It can be anodised to achieve beautiful colours: yellows, pinks, purples, blues, and greens.
It’s a transition metal and in its pure form can be cold worked from sheet using the technique “chasing and repoussé”.
Alice's research into titanium and niobium as an alternative source of colour to gemstones has lead her to explore the technique of anodising.
The colour chart below shows the range of colours that niobium can be anodised to.
How does anodising work?
This technique creates a niobium oxide layer on the surface of the niobium metal by passing electricity through the niobium whilst submerged in a bath of bicarbonate of soda dissolved in water.
Different voltages create different colours. The higher the voltage, the thicker the oxide layer. Multiple colours can be achieved by masking off areas, or using an electrified brush.
The niobium oxide layer is actually transparent. It’s the way the light refracts and reflects through this material that creates the “interference colours”. Wavelengths of light are cancelled out, leaving the colour that you see. This works the same way as structural colourisation on butterfly wings. These colours are iridescent and create flashes of different hues at different lights and angles.
The higher the voltage, the thicker the oxide layer, creating different colours as shown above.