Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Etching titanium
Q. I am trying to remember a titanium etch based on EDTA. I need an etch that has no HF and would prefer not using hot H2O2. Can you help?
Chet Brewer-Durham, North Carolina
2001
A. Dear Chet,
I am sorry that I can't give you an answer to your question in the moment. I am looking for a process to remove a thin Titanium layer (15nm) without destroying the underneath Oxide layer (Therefore I can't use HF). Do you have an idea? Thank you in advance and best regards.
Ralf SteingrueberHeinrich-Hertz-Institut - Berlin, Germany
2002
Q. Does anyone know how can I etch titanium with low speed (max 100 Angstroms /min )?
Thanks,
Novello F [last name deleted for privacy by Editor]- Roma, Italy
2002
Q. I am looking for an etchant that will remove a one micron layer of Titanium film without any effect on the gold layer under the titanium.
Any suggestions?
Can one explain the chemistry of the etching process?
Thanks
Electronics device developer - Jessup, Maryland
2006
A. Dear Anil,
Try 0.5% HF solution. (Take necessary safety precaution). If your Ti layer has a thick oxide layer it will be while, but once the oxide layer is gone the Ti layer just crumbles you can see the H2 bubbling from the solution.
regards,
- Austin, Texas
2006
A. You can try HF with various concentration. Since you only want to etch 1 micron, start from the low side. Plus, you can add CrO3 or HNO3 to HF. I heard acetic acid
⇦ this on
eBay
or
Amazon [affil links] also etches
Ti, you can give it a try.
metal processing - Taiwan
2006
Multiple threads merged: please forgive chronology errors and repetition 🙂
Q. We are making very small titanium parts for the consumer industry. We are investment casting various titanium and zirconium alloys. We want to try etching with concentrations of pure Nitric and water rather than mess with Hydrofluoric.
These are not aerospace applications although some are medical. Can I do this?
- Fort Myers, Florida
2006
|
A. I can surely be wrong, but I doubt if any concentration of nitric will etch Ti. You do not have to use HF acid which is nasty!It does go from being an 800 pound tiger to a wild pussy cat with lowering%. The safer option is to replace the HF acid with ammonium bi fluoride which is a white crystal. The resulting nitric- ammonium bi fluoride solution is not much worse than the nitric alone. It does require proper training and safety equipment. You should also talk to your local hospital or emergency services so they can carry the correct burn materials. If they look at you like an idiot, tell them to look up the treatment for HF acid burns. James Watts- Navarre, Florida 2006 A. Try a mixture of 5% sodium hydroxide and 5% hydrogen peroxide for etching titanium. It is a fairly slow process, requiring possibly an hour or longer, depending on how deep you need to etch.  Jeffrey Holmes, CEF Spartanburg, South Carolina 2006 |
Titanium etch (polishing) for anodising purposes
Q. Hello,
I make Swiss knives and some are made out of or with parts of titanium, either CP or 6al4v
For anodising it to bright colors I have to high polish them, that's tough and intensive work and if I have, say, milled grooves etc I can't manually polish it down in there... so I think about etching that titanium surface...have asked my chemical supplier and they have no idea...any suggestions?
thanks a lot!
swiss knives - Worb, Be, Switzerland
2006
A. Hi. Weak HF 1% but may give fine grain etch.
Hydrofluoric Acid.
inventor - Wales
2006
2006
adv.
If you want high-level polish without any environmental issue we suggest to contact us about titanium electropolishing technology in acid-free electrolyte. You can polish many pieces together. No special equipment is required.
Anna Berkovich
Russamer Lab
Pittsburgh, Pennsylvania
Multiple threads merged: please forgive chronology errors and repetition 🙂
Titanium etching without HF
Q. Hi,
I need to etch titanium parts before anodization, I know the usual HNO3 + HF etchant. But I need to have very polished surface before anodization, like a mirror, and the etching makes my surface rougher.
Does anyone know any etchant that does not affect the roughness of the titanium substrate?
UPC - Barcelona, Spain
2006
A. Ammonium bi fluoride is a safer source of fluoride ion, but HF is easier to use (ignoring safety). What you need is a weaker solution and keep your nitric content at about 14 times the HF content. When it gets below 10X you run a risk of serious pitting.With the weaker solution it is easier to find the least amount of etch that will serve your needs. That is because the reaction is going slower.
Try it in the lab on some scrap that you polish.
- Navarre, Florida
2006
A. Try www.uspto.gov webpages,patent no.4 554 050(EDTA based titanium etchant).Hope it helps and good luck!
Goran Budija- Cerovski vrh Croatia
2007
Q. Pablo
I need etching Titanium metal can you show me the solution, concentration and time. Thank you in advance.
- Hanoi and Viet Nam
April 2, 2008
Q. I find that there is some staining of titanium and sometimes tungsten, utilizing common etching chemistry. This appears surface in nature. Any feedback?
Karen M. Schlichter- Plymouth, Massachusetts
2007
Multiple threads merged: please forgive chronology errors and repetition 🙂
Q. I would like to know the correct proportion of the etchant for Titanium. I use an etch with 1.8% HF, 5.6%HNO3 and water. This etch clearly etched Ti deposited in one machine while it doesn't etch the Ti deposited in another similar sputter system. The two Ti films differ only in the amount of oxygen present in them. I am wondering whether the etch that I use is very mild so that it etches only the impure films.
ANNIE KURUVILLAresearcher - Canada
2007
2007
A. Try upping your concentration of nitric... I don't know how it will perform under your conditions but I know that I've maintained a Ti etch bath at 2.5 oz/gallon HF and 55 oz/gallon HNO3.
Good luck!
Compton, California, USA
A. To avoid pitting, keep the nitric strength about 14 times the HF concentration, and no lower than 10.
You might want to have an outside lab check your concentrations. If they are really identical, they both have to work.
The other variable is the amount of dissolved Ti. As it builds up the rate of reaction decreases drastically.
- Navarre, Florida
2007
Titanium Deox/etch
Q. I am doing some titanium anodizing and discovered that etching the parts prior to anodize tremendously improves the color and luster throughout the spectrum. I dip the parts in a mixture of HF and Nitric acid for a few seconds and it works wonders. However, the issue I have is that I need to transfer the parts from the acid bath to a rinse solution VERY quickly or the parts react 'undesirably' with the air during the transfer resulting in a white smut on the surface. Is there a better way to do this to retain the nice clean luster that the HF/Nitric bath produces and avoid having to re-dip?
Adam Marchese- St. Augustine, Florida USA
November 30, 2017
Adam,
We use our own formula of "greener" version to clean titanium prior to anodizing. The colors are of not so 'poisonous" shades, as after regular etching.
adv. Contact me for consulting.
Also we can recommend titanium surface preparation under small electrical current. This method works fine for basket color anodizing.
Anna Berkovich
Russamer Lab
Pittsburgh, Pennsylvania
December 11, 2017
Q. I would like to etch oxidised layer of Titanium in the way that only thin layers are dissolved by etchant and not too much effect on strong thick oxidised one. Is this possible?
Could anyone please suggest me any acidic solution? (which may cause pitting in weak areas)?
- Australia, Adelaide
January 19, 2018
A. Hi cousin Arash. The acid doesn't know which oxides you wish to attack and which you don't. So hoping that it will completely dissolve it in some areas while not doing significant dissolution in others is chancy.
The way that selective etching is usually done is to mask the areas you don't want etched, and remove the masking after the etching.
You haven't told us anything about YOUR SITUATION yet, but if this is just a one-time hobbyist project, it's possible that something as simple and ubiquitous as electrician's tape will serve as a maskant. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
January 2018
Q. Thank you for your kind reply.
As far as I understood some sections on the surface of titanium can be corroded prior to others, particularly those sites which exhibit higher surface energy than others, my main question is, having lower oxide thickness, when it's compared to thick one, can be regarded as the sites with higher surface energy and finally get corroded faster?
In other words, can difference in thickness of oxide layer lead to localised corrosion? If so, how?
- Australia, adeliade
January 23, 2018
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