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Ted Mooney, P.E. RET
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for Metal Finishing 1989-2025
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Need titanium anodizer for multi-color sheets for kitchen cabinets
Quickstart:
Titanium can be colorized relatively easily for jewelry and similar purposes by anodizing, which converts some of the titanium metal on the surface to titanium oxide. Most of the individual colors of the rainbow are possible, as is a multi-colored iridescent "oil slick" look. These colors are not pigments or dyes, but sort of an illusion called "interference coloring" ...
Passing white light through a glass prism separates it into the colors of the rainbow because each color is a different wavelength. Similarly, the titanium oxide formed on the surface is actually colorless and transparent/translucent. When light reflects from anodized titanium, half (or so) bounces off the surface, while half penetrates the clear anodizing and bounces off the titanium. The two halves have traveled different distances, differing by a "partial wavelength", amplifying or attenuating different wavelengths/colors. The perceived color depends on the thickness of the anodizing.
Titanium anodizing is done in trisodium phosphate or phosphoric acid or even Coca-Cola. The hazard for hobbyists is that high voltages must be used for some colors; safety requires wearing insulating gloves, never touching anything with the power on, and using an "isolation transformer" for high voltages.
An alternative to making items out of titanium and then anodizing them, is to make them of another material like stainless steel and apply a partial wavelength thickness of titanium oxide in a PVD (physical vapor deposition) vacuum chamber. These chambers are multimillion dollar items and easily contaminated, so this alternative is for high volume items, not onesy-twosy custom jewelry.
RFQ: Hi,
I am looking to find someone in the UK who could help me create multi-coloured anodised thin titanium sheet to use on cupboard door fronts and draws for a kitchen.
Finding the sheet isn't too tricky but decorative anodising on a small scale doesn't appear to be widely practised.
Any steers, contacts, suggestions or not overly technical advice would be much appreciated,
Thanks in advance Chris
- London UK
August 1, 2024
privately respond to this RFQ
Ed. note: As always, gentle readers: technical replies in public and commercial replies in private please (huh? why?)
A. Hi.
Fixed colors like pink, blue, purple, or green are obtained by anodizing for a fixed amount of time at the appropriate voltage for that color. Rainbow hues are obtained by dipping the sheet such that various areas are exposed to varying times and/or voltages. I believe that most titanium anodizing is done on small items like jewelry and pocket knives, and that you may have a hard time finding a production facility for sheets.
Please introduce your situation: if you are a homeowner wanting this for yourself, or an architect wanting it for one kitchen, it is not high-tech stuff, and a local artist could probably obtain tanks and get it going for you. However, if you are a cabinet manufacturer, I think you're probably going to need to set up your own production facility, or have one set up at a job shop for you.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Thanks Ted appreciate your input.
It is both for my own home project, and as such - as a trial for my commercial office interiors design and build business, to prove the concept.
I understand the anodised coat is fairly thin, and can be subject to finger prints - any suggestions as to what best to use as a clear projective coat?
Also the shinier the sheet you start out with the shinier the result?
Best thing to Polish titanium sheet prior?
Thanks Chris
- London
August 5, 2024
A. Hi Chris.
I am not certain that it can be coated with anything :-(
I would suggest anodizing a piece, or buying titanium knives or pieces of jewelry if easier, and trying various clear coats on them to see what they do to the colors before going any further. The problem is that the coloring is not a pigment of any sort, rather it's a partial wavelength thin-film interference coating...
Half of the light (or so) bounces off the outside surface of the anodizing; the other half passes thru the transparent titanium oxide anodized coating and bounces off the titanium base. Since half the light travels that extra distance, the interference means the reflected light offers diminution of some wavelengths and amplifications of others, i.e., some colors of the white light are enhanced and some are suppressed, creating the colors you see. When you add another clear layer on top of it, it's certain that it won't work as well. Whether it will work acceptably is hard to predict.
Yes, the shinier the surface before anodizing, the shinier after.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. Probably it can be hardened in hot 2-5% sodium silicate solution (according to some patents that process can be used on anodized stainless steel -- I think that process must work on any color anodized metal). Hope it helps and good luck!
Budija Goran- Cerovski vrh Croatia
September 9, 2024
A. I think that PVD is much better option (you can buy some PVD colored cutlery for testing.
Excellent article on use of PVD for jewelry(1996.!!!):
https://www.santafesymposium.org/1996-santa-fe-symposium-papers/1996-physical-vapor-deposition-of-decorative-coatings-for-jewelry
Hope it helps and good luck!
- cerovski vrh Croatia
A. This type of surface color anodizing can be easily obtained by slowly submerging the titanium piece under electrical current into the anodizing tank.
Anna Berkovich
Russamer Lab
Pittsburgh, Pennsylvania
February 8, 2025
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