Tantalum Foil Drawing Cracks after First Operation 4

[catcheral]

Hi Colleagues,
Recent tantalum .002" foil material (either e-beam melted or arc cast) has tearing problems forming small cup shapes, while 5-10 years old vintage material (.0023 to .0024" thick) does not. The source of the old vintage material cannot be verified, but we can can assume that both materials came from the same supplier. Recent material is slightly harder than the older material (120 KHN vs 90-100 KHN). We tried to anneal the material once and even twice without any improvement.
Has anyone ever run into this problem?

Any suggestions on sources for high purity Ta foil?
Thank you.

 

[metman]

You might try Scarrot Metallurgical if they are still an operating business. Their specialty was refractory metals furnace brazing, heat treating, etc.

If Scarrot is no onger operating, one of the priciples was a man by the name of Robert Fairbanks, now retired. Bob was an associate of mine and a very sharp metallurgist. He might still be an ASM member even though retired and maybe could be contacted via ASM if a member.

 

[btrueblood]

Star for Metman. Scarrot operates (ed?) out of Southern California (LA) if memory serves.

 

[unclesyd]

Here is the Tantalum Technologies site. We had a lot of deraling with them and no problems.

http://www.tantalum-coating.com/index.htm

One thing I remember is that working on making extrusion jets for synthetic fiber we had some problems when we changed the die material. The problem was solved by using a lubricant where we hadn't before. A totally different lubricant was needed when we perforated the formed Ta. There were some discussion at the time about the behaviour of Ta in contact with other metals.

 

[metman]

http://www.scarrott.com/

Sorry it was late and I was tired lasst nite so did not think to Google it until I read btrueblood's comment.