Alchemy with Electricity: The Science and Style of Anodizing & Thermal Oxidation

Alchemy with Electricity: The Science and Style of Anodizing & Thermal Oxidation


The Accidental Color Revolution

Back in 1923, a clever British chap named Bengough and his pal Stuart were trying to protect aluminum from corrosion. What they stumbled upon was something that changed the surface of metal design forever: anodizing. Originally developed for industrial protection (think aircraft parts and sea-weathered rivets), anodizing was never supposed to be beautiful. And yet—here we are.

——US Navy HS-2L’s wings were anodized to protect them from degeneration

How Anodizing Works (a.k.a. How to Electrify a Rainbow)

Anodizing is a controlled electrochemical reaction. A metal—usually titanium or aluminum—is dunked into an acid bath and zapped with an electrical current. This causes an oxide layer to grow on the surface. Unlike paint or plating, this isn’t a coating that sits on top—it becomes part of the metal.

Here’s the magical bit: by adjusting voltage, you control how light refracts off the surface, which creates iridescent colors without dyes or pigments. No two anodized surfaces ever look quite the same, making every piece subtly unique.

Enter High-Temperature Oxidation (Because Some Like It Hot)

While anodizing uses voltage and acid, thermal oxidation cranks up the heat instead. In this method, metals like titanium are heated in a controlled environment—often upwards of 500°C. The high heat draws oxygen into the surface, creating a vibrant oxide layer rich in color.

Different times and temperatures impact of oxidation of copper 

Compared to anodizing, thermal oxidation often creates deeper, warmer hues—coppers, purples, golden ambers—that feel earthy and elemental. It’s less about sharp lines and more about organic gradients that evoke natural mineral patterns.

Why POSAN Loves Oxidation (of All Kinds)

At POSAN, color isn’t just decoration—it’s structure, spirit, and statement. Anodizing allows us to render brilliant teals, magentas, and golds from pure titanium without adding anything unnatural. And with thermal oxidation, we dive into darker, bolder territory—burnished bronzes, volcanic reds, metallic charcoals.

These aren’t colors that flake or fade. They’re burned into the metal’s memory, lasting as long as the piece itself. It’s controlled chaos, captured in color.

The Science of Style

Electrochemistry might sound clinical, but what it creates is almost poetic. Each adjustment in voltage, temperature, or airflow changes the final result. An anodized or thermally oxidized POSAN piece is part science lab, part forge, and part artist’s studio.

 

That’s why we embrace both. Because metal deserves more than silver and grey. It deserves a personality.

Further Reading & References

  1. Bengough, G.D., & Stuart, J. "The Protection of Aluminium and Its Alloys." British Patent No. 223,453 (1923).

  2. Diggle, J.W., Downie, T.C., & Goulding, C.W. "Anodic Oxide Films on Aluminum." Chemical Reviews, 1969.

  3. Zhang, Y. et al. "Color Formation Mechanisms of Titanium Oxide Films." Applied Surface Science, 2010.

  4. Wernick, S., Pinner, R., & Sheasby, P.G. "The Surface Treatment and Finishing of Aluminum and Its Alloys." Finishing Publications Ltd., 1987.

  5. Williams, D.E. "Thermal Oxidation of Titanium Alloys for Biomedical Applications." Journal of Materials Science: Materials in Medicine, 2008.

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