Titanium Anodizing / finishing

[EZ3PUTT]

I have some Titanium parts that I want to have finished with some sort of coloring. Anybody have any experience with Titanium anodizing or other finish possibilities? Will powdercoat take to Titanium? Any other options available?

[Andy]

One of my customers makes titanium, niobium jewelry. They hang the ti or niobium in a tub of water. The water may be saline or have salt in it.

In the tub there is a plate (probably copper) and hook a wire to it. Another wire goes to the jewelry. They put a DC voltage on the wires and walaa, color. Not sure about polarity. The power supply is variable say 0-30 DC. The interesting thing is that different voltages make different colors. Apparently the surface molecules are rearanged to refract light differently as in a prism.

You could try this in a coffee cup and use a car battery. It takes about 3seconds to color. I've watched them and it is pretty amazing.

Let us know what happens.

[Philcott]

Easy,

 

I got this from finishing .com

 

Use the search engine at the bottom of the page type in "coloring titanium".

 

Phil

 

What is the best solution for anodizing titanium alloys? Also, what current and voltage ranges are appropriate to achieve a gold color.

 

Robert H. Rhea - Steri-Oss

 

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Sat, 7 Jun 1997

Mr. Ken Lemke, who hosts our chatroom (see times for chatroom, available from our home page) mentioned that he purchased some anodizied Ti ear rings. (Ah, I see, you have bored a hole in your ear). Maybe he remembers the company that fabricated them.

 

I have seen these beautiful objects, and perhaps there are several solutions that can be used. Do you have the facilities to run some tests

 

 

Tom Pullizzi - Bayside Electrical Testing, Inc. - Beach Haven, NJ

 

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Mon, 9 Jun 1997

I have heard that the color changes with the voltage rather than the amperage. The exact alloy will very probably make a large difference in the exact voltage. Try 10 -15% sulfuric.

 

James Watts - Fl

 

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Tue, 17 Jun 1997

A bath that can be used for anodizing titanium is

 

phosphoric acid 80 w% Room temperature

sulphuric acid 10 w%

water 10 w%

 

The bath is controlled, as mentioned by James Watt, by the voltage. The voltage is critical.

 

Good luck.

 

J.H. Pennings - TNO INSTITUTE OF INDUSTRIAL TECHNOLOGY - Netherlands

 

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26 June 97

I have been coloring Ti for decorative use (on a small scale ) using Coca - Cola and stainless steel cathodes, powered from my anodising rectifier at + - 60volts . The trick is in how long you dip it , the longer , the darker . A couple of seconds is normally enough . It's a great party trick . By the way , the color is dependent on the lighting , and finish of the part , it is caused by difraction of the light waves.

 

Dave Brackenridge - Aerospace Electroplating

 

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Thu, 26 Jun 1997

Oxalic Acid, Phosphoric Acid (Coke Cola) Sulfate of Ammonium (Fertilizer), TSP (All Purpose Cleaner)

 

All of the above mentioned chemicals will anodize refractory metals.

 

I have been anodizing refactory metals for the past 17 years and have not added sulfuric acids to my solution. Keep it simple and friendly.

 

Bernie Wire - Wire Works

 

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Tue, 24 Jun 1997

Color anodizing titanium for appearance (not functional) can be achieved in most any sulfuric anodizing or hard anodizing bath by first cleaning the titanium in a nitric/hydrofluoric bath (25-35% nitric with 2-4 oz/gal hydrofluoric) for about 10-30 seconds. You then anodize the parts by slowly raising the voltage from the starting voltage. Color changes occur about ever 2-4 VDC. Color changes occur much like octaves on a piano - as you increase voltages the color changes will proceed thru several octave ranges. When you achieve the color you are seeking, record the voltage and anodize subsequent lots at that voltage - no need to raise the voltage slowly once it has been determined.If you don't like the coating, strip in the nitric/HF bath and try again. Good luck.

 

Kent Backus - Har-Conn Chrome Co

 

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Tue, 6 Jan 1998

Robert,

 

I use a trisodium phosphate solution (3% to 5% by weight) to anodize titanium and niobium. This solution is quite safe and gives excellent colors in a small scale operation. The quality of the color achieved depends on the surface finish of the part and its cleanliness, (free of dirt and all oils). Current should be low: I use about 2 amps on small parts. The bath should be kept below 80 degrees farenheight. If the bath is too hot or the current too strong, the part will be etched and turn grey. The part must then be polished and anodized again. The voltage is what determines the color. I use a range of 20 to 75 volts. If I remeber right, yellow occurs at about 42 volts. Also, I have read that it is best to use a cathode of the same material that you are anodizing.

 

Howard Bailey

 

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Thu, 15 Jan 1998

I would like to build a rectifier for anodizing titanium. I know it should be DC but the only ones I have seen go up to 200V DC which seems quite a lot. Do I need something this powerfull and are there any other specifications I should know about?

 

Adam Wittig - A@E Metal Merchants

 

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October 15, 1998

I an using TSP mixed with water to color small titanium parts and would like to know around what voltage would i need to get a gold color,, im useing 3-4 9volt batterys and have only got a really nice blue or purple. please help!! What would it take to get "GOLD"

 

Mike wilson - - ca

 

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Fri, 16 Oct 1998

Keep adding batteries in series until you get a goldish color. From a test piece on 0 to 200 volts, gold is near the middle. Unfortunately, 1 or 2 volts makes a difference in the exact shade that you get, so you will have to take what ever is near. As the batteries age, you will not get the exact color that you once did.

 

James Watts - Fl

 

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October 20, 1998

when coloring titanium, what would be a better solution to use, TSP, or Sulfate of ammonium (Fertalizer)? or would a combination of the two work better? It's for little titanium parts. with 9 volt batterys being my power source. Please give me any information on the topic.

 

Thank You

 

Mike wilson - - ca

[mike_f]

ah, now I get it I used to wire edm quite a bit of titanium. this funky hue always appeared and changed in itensity from the cut surface outward, almost like steel will blue from heat. I knew it couldn't be heat but could never explain it. cool.

[CAM-mando]

LOOK HERE

[EZ3PUTT]

Found a company in Colorado Springs that does Titanium anodizing. Took one of my parts down last Friday just to see the color options. He went ahead an did my part even though it was not yet completed. It will be polished and done again after polishing, but man does it look good.

[Harryman]

quote:

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niobium jewelry

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What is the reason for making jewelry from niobium? Other than the fact that it's very exotic to most people, it's really a pretty boring metal. ZZZzzz.