Dissolution of Inconel 617/Haynes 230

[rams210405]

I am trying to dissolve the nickel-based alloys Inconel 617 and Haynes 230 in order to analyze the precipitates with XRD. I already tried the Berzelius solution which is 47.7 g of copper (II) chloride, 41.7 g of potassium chloride, 2.9 g of tartaric acid, 275 ml of distilled water, and 22.4 ml of hydrochloric acid. While this worked for several steels it had almost no effect on the nickel alloys. If you have any ideas on what might work please help!

 

[MrSid]

If you have access to Perry's Chemical Engineering Handbook, you can find some of these exotic alloys and their corrosivity charts to many chemicals under a number of conditions. The inconels and Haynes alloys are made for Halogen acid resistance and are also resistant to oxidative conditions. The solution you are using is made to apply oxidative Cl- attack and keep the metal ions in chelated solution.

A reductive (hot CO) can remove Ni as the poisonous Nickel Carbonyl gas and leave the alloy largely destroyed or embrittled. If the goal is recovery of the elements of the alloy this won't work, but there may be some combo that will achieve a similar chemical route to corroding the metal in a quantitative manner.