Letter 1265

Anodizing titanium

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We want to anodize titanium using a alkaline anodizing bath. Who can give use the formulation of a alkaline anodizing bath. We want to get a gray coating.

Any advice would be appreciated.

J.H. Pennings
TNO Institute of Industrial Technology - Netherlands

See AMS2488 [link is to spec at TechStreet] - the anodizing is performed in an alkaline solution of pH >= 12 (going by memory only, may be pH >13). Unlike anodizing aluminum, the colour is not uniform and not controllable (almost). Depending on the alloy (and solution?!), we are getting yellow to blue through grey appearance.
Max

Max Stein
- Montreal, Québec, Canada

With titanium in a bath of Trisodium Phosphate [link is to product info at Amazon] you get the most beautiful color of blue imaginable. All you need to do is to immerse the part, turn on the current and voilà , bright blue. Not gray but close??

Dave Fairbourn

Thanks Dave. To minimize confusion, though, we need to tell the readers that there are two general types of titanium anodizing. The "alkaline anodizing" is a heavy, wear-resistant, anti-galling surface for engineering applications. The acid or neutral anodizing you are describing is a very thin very colorful diffraction coloration for decorative jewelry and similar applications.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

I've been trying to find out how to anodize titanium and magnesium. I need to know what should be the current, voltage and electrolyte concentration. What kind of colours can be obtained? What kind of post treatments are needed?

Mikko Pelkonen
Tampere University of Technology - Finland

A true grey from TSP is not probable.

Brown, blue, silver, yellow, purple and green are possible at voltages up to 200. There are several different shades possible for each. Precise color requires precise voltage control. It anodizes nearly instantly. Surface prep makes a significant difference in the luster or look of the product. Does not need any further protection after anodize.

From 10% to 3% solutions are recommended.

James Watts
- Fl

We want to anodise titanium and titanium- aluminum by the colors gold, blue, grey and purple. I need to know what should be the current, voltage and electrolyte components and concentrations.

Any help will be appreciated!

Many thanks!

Robert Kistler
- Nussbaumen/ Switzerland

I, can any one help finding a way to relate the colour you see, when titanium gets oxidated, and the thickness of the oxidated film. I know it is an optical interference, but what colour corresponds to what thickness??? Thanks

Filipe Teixeira
Oporto University - Oporto

A magazine called Xtreme R/C Cars will publish an article on ti anodizing in an upcoming issue. Sorry I don't know what month, but issue 4.9 I think. I am interested in ti & alum anodizing, and would like to obtain a red color. Any info is greatly appreciated.

David Thomason
Glendale, AZ

The color red is not possible with titanium anodizing nor is black. Apparently neither exists in the spectrum created by the oxide layer formed on the surface. The color exists only as reflected light.

Dennis Rand
- Plymouth, MA

How can I tell whether an item is titanium or aluminum? Nelson Helm

Nelson Helm
Louisville, KY

Look up Properties of Titanium in the 1948 Metals Handbook, American Society for Metals, page 1143, I, General resistance to corrosion.

Compare to aluminum in how it is processed for finishing. Make sure you are talking about pure aluminum and pure titanium, since titanium will alloy with aluminum. This is leading to a destructive chemical spot test.

Tom Pullizzi Platronica.com Falls Township, PA

The cheapest, simplest, non-toxic way was discovered by Archimedes and I've used it to distinguish between aluminum and zinc diecastings myself--

Weigh the item, then immerse it in a bucket or container that was full to the brim. This container should be inside a second container to catch the overflow.

Measure the volume of water displaced, or weigh the water displaced--whatever is convenient. The ratio of the weight of the item to the weight of the displaced water is the specific gravity of the material. Now you just look up which material has that specific gravity.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

I am anodizing a 6al-4v ti medical device blue,yellow & green. These parts are subjected to 250ƒF steam autoclaving for sterlization. Some of the parts after two cycles of autoclaving (40 min/cycle)are beginning to change to the next color. (yellow - magenta, blue-clear). This is only happening in a few parts but I need help into why it is happening and how to stop it. If anyone has suggestions I would appreciate the help.

Jim Johnson, Sr. Design Eng.
- carlsbad,ca

I would like to receive some SEM images of Titanium (Ti 6Al4V) Oxide due to sulphuric acid anodizing. Thank you!!!!

Livia Cubuzio
- Naples, Italy

We can produce and reproduce stable and controllable colors for titanium anodizing. Technology is ready for licensing.

You can see shades available on our web site. Black color can be obtained also, but this is a different technology.

Anna Berkovich Russamer Lab Pittsburgh, Pennsylvania

I have done gold plating and rhodium plating but I have never done anything with titanium.

I'm looking for more information on anodizing titanium, such as what voltage will give off what color.

Also the solution I have to use, is it just water with TSP? or just distilled water alone?

Thanks,

Harry Kabadaian
designer - Los Angeles, CA, USA

Dear Sirs,
I am a manufacturer of Orthopaedic Implants made of S.S.316L and Ti-6AL-4V ELI. I am looking for Anodize per AMS2488 [link is to spec at TechStreet]c Type I Colors (Pink, Gold and Green).

It will of grest help to me if you can tell me the procedure for it.

Thank you.

Lokesh Jokiani
- Delhi, India

I am new to the anodizing process and am having problems anodizing titanium green. The pieces are about 2 and a half inches long and are a half inch wide. When I anodize these pieces in other colors I have very little to no problems. I was wondering if this could be environmentally affected (humidity) or is this a normal problem for larger pieces.

Terry Donnalson
hobbyist - Lititz, Pennslyvania, USA

Alkaline Anodizing of Titanium Ti-6AL-4V. I am looking for the exact bath solution for what I have been told is a type II anodize per AMS2488 [link is to spec at TechStreet]D.

I understand that it is >/=13 pH and that the temperature is controlled to +/-2F and that voltage is the controlled characteristic, but WHAT is the chemical?

Vicki Dominguez
medical device industry - Huntington, IN, USA

Hi, Vicki. I know it's strange and you'll say "how can that be?", but . . .

- even though the alkaline anodizing process is covered by AMS spec . . .

some of the details of the alkaline anodizing process are trade secrets. You have to figure out these details for yourself, or you have to retain a consultant who will give them to you; you won't find them in the literature or in a public forum. Sorry, and admitedly it makes no sense, but there it is :-)

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Dear sir,
I try to anodize titanium size 1" x 4" to pink and green color by use TSP and Borax but the color not pure, for pink color will have light blue and green color will have yellow. And it not shiny like gold,purple or blue that I do the same method. What solution I have to use for high voltage anodized and more method I should do?
Thank you and very best regards.
Thita M. ( from Thailand )

Thitaree Manosittisak
- Bangkok, Thailand

^-- I want to contact this person and my company is a supporting advertiser of finishing.com

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