Help with anodising titanium please!

I hope there might be someone out there who can offer a bit of advice & assistance!

I have previously had some success anodising small pieces of titanium using 9v batteries & Coca Cola (strange but true) and decided to go mad & buy some "proper" kit in the hope that it might make the process easier. I am now the proud owner of a 1amp, variable voltage (0-120) benchtop power supply, but having donned my safety rubber gloves and taken a very deep breath (all those volts + liquid is scary stuff!) I am having a few problems.

I have Grade 1, 0.5mm Ti sheet which I have prepared by degreasing in an ultrasound bath, then soaked in Titanetch, rinsed in Sodium carbonate solution & anodised using ammonium sulphate (I have tried 10 & 20% solutions) I have managed to obtain passable gold, blue & purple colours which seem to develop at much lower voltages than I expected, but I am unable to get anything approaching pink, teal or green. My understanding was that the colour is largely voltage dependant and to get the pink to green range I would have to crank the voltage up towards 100, but when I do this (incrementally) all I am getting is a lot of fizzing, sparks which look a bit like a microwace arcing and a very dull, almost lilac matt colour finish. I am using Ti wire to hold the pieces in the solution, btw.

Can anyone offer any advice? I am not sure if it is the solution I am using, my prep technique, the electrical bit, or the holding wire which is causing problems. It seems (with my limited knowledge of physics and metallurgy!) that somehow the oxide layer is preventing the colours forming? (Excuse me experts if this is a daft thing to say ;-))

Thanks in anticipation!

greneeyedleo

Hi Leo,

If what you bought is the SMT Micro Anodiser from Reactive Metals, you will have read the pamphlet: Studio Preparation and Colouring of Titanium, which also comes from there. That is virtually all the information available, except "a cheap and dirty method of anodising..." Which describes the use of batteries.

I have coloured niobium using a brush-on technique and had no problems achieving all the colours using trisodium phosphate as they suggested, so maybe Cola is not the best electrolyte at the higher voltages. unfortunately my thread cannot be accessed now due to a fault , but here is a picture of my test piece. I bought a small quantity of TSP From Mistral.

Regards, Dennis.

Maybe Geti would be able to help you there as Titanium is his main thing........

you need to etch your titanium. You will not get good anodizing if you do no etching.
But I happen to stumble on your post looking for "titanetch" results. But looks like you are talking about a different titanetch than I was looking for. I am using some etchant called "Titan-Etch" for etching, and today I got some really good results. I could anodize to green! While in the months before I could get some blue and purple if I was lucky. So find a good etchant! Hope this helps

A very old post to be resurrecting...

If it's this stuff - http://www.titanetch.com/index.php then it's mostly sodium fluoride, which dissociates in water giving you the same fluoride ion as HF does. So marginally safer in storage, but not really any safer in use.
However, they don't ship to the UK at all.

I have been anodising titanium for a while now in the workshop, but am not happy yet adding it as a paid option.

The problem I have is the colours are a bit wishy washy and not vibrant enough.

My system is polish, ultrasonic, rinse and dry without touching and then anodising with trisodium phosphate.

Now reading this post it may seem I need to etch my titanium. The only thing is I don't understand what this process is, or where it would fit in.

Would someone possibly explain, or point me to any articles, videos etc that may help.

For interest here is a ring I anodised https://www.facebook.com/TitanJewell...type=3&theater

Many thanks

Jason

For more information, contact Reactive Metal Studio http://www.reactivemetals.com/Home.html Dennis.

Many thanks,

Some scary stuff in those instructions. It would seem this is what I'm missing.

Unfortunately for getting vibrant color in the higher voltage ranges there is no way around etching. This entails the use of some fluoride containing solution with all the hazards involved. using NaF just makes a weaker solution of fluoride ions but they still are present.
I also found that grades 1-4 (thats practically pure ti) do produce a more washed out color than grade 5 (6al4v) even with previous etching. Colors on grade 5 are better than on grades 1-4. But Gr.5 ti is also much harder to work with...
you can always change to niobium or tantalum, this colors beautifully even without etching.

Many thanks Ralph.

The titanium we use is 98 to 99% pure so would assume its one of the lower grades.

I am almost happy with my set up and only need a little improvement, and more consistency which I hope etching will do.