Etch Formula for Tantalum Microstructure 2

[CoffeeMan]

Does anyone know of a formula that will reveal the microstructure of tantalum?

We are cutting .080 tantalum in a CO2 laser. To evaluate the quality of the cut we must cut a cross-section and look at the recast layer and grain boundaries of the base metal. So far we have used the etchants we have on hand (kalling's, hydrochloric, nitric) none of which have had much effect.

Best regards,

CoffeeMan

 

[Rich2001]

Try

10g NaOH, 100 ml water

 

[EdStainless]

OK, this is out of Petzow, "Metallographic Etching"

Macro etch, 30ml HCl + 15ml Nitric + 30ml HF
(hey, it wasn't my idea)
Microetch
90ml sulfuric + 10ml HF
or
50ml sulfuric + 20ml nitric + 20ml HF
and about 6 more, all with HF in them.

OK, so you want one without HF in it. Here is an electrolytic etch that should work.
75ml methanol + 10ml sulfuric + 25ml HCl

We have a lot of HF around here so that wouldn't bother me, but the stuff can be very dangerous.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[EdStainless]

One more thought, have you tried heat tiniting the samples? A simple bake in an oven and then viewing under polarized light may be all that you need.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[BeliefMakr]

Tantalum is almost completely immune to chemical attack at temperatures below 150C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly.