I want to study different corrosion forms of nickel and nickel alloys. As IGC is somewhat challenging to study, has anybody a suggestion or some practical input of:
- what corrosive liquid I could use to get a nice example of IGC on nickel?
- or maybe recommend a paper or a book ? I have read already the nice paper of Kasparova; Intergranular Corrosion of Nickel Alloys (Review). Prot. of Metals, Vol. 36, No. 6, 2000,
- or a standardized procedure which deals with IGC? I already read ASTM G28.
Dear Dr. Johan Vanbrabant ,
as you said, ASTM G28 was designed as common standard method regarding IGC for nickel-based alloys.
I suggest you to have a look at the following note/papers:
-Intergranular Corrosion Tests for CRA’S by NeoNickel
Available at: https://www.neonickel.com/it/technical-resources/technical-papers-it/intergranular-corrosion-tests-cras/
-Structure and Corrosion Resistance Against Intergranular Corrosion of Nickel-based Superalloy VDM ® Alloy C-4
Alfiya Gibadullina, Arkadiy Zhilyakov, Andrey Shak, Ilya Polovov
In MIE-2017
Available at: https://knepublishing.com/index.php/KnE-Materials/article/view/2151/4842#toc
-Intergranular Corrosion Behavior of Nickel Base Superalloys 600, 690 And 693
Pradeep Kumar Samantaroy
International Journal of Engineering Research & Technology (IJER), Vol. 9 Issue 01, pp 470-474 (2020)
Available at: https://www.ijert.org/research/intergranular-corrosion-behavior-of-nickel-base-superalloys-600-690-and-693-IJERTV9IS010259.pdf
Best regards, Pierluigi Traverso.
Dear Dr. Pierluigi Traverso,
Thanks for the feedback. The tables of the NeoNickel webpage are a good overview.
Thanks for your reply. Much appreciated,
Johan
Hello Johan :-)
It is also possible to adapt electrochemical methods for testing for IGC in nickel, namely the electrochemical reactivation test, see also here:
Development of an electrochemical reactivation test procedure for detecting microstructural heterogeneity in Ni-Cr-Mo-W alloy welds
https://link.springer.com/article/10.1023%2FB%3AJMSC.0000017802.98188.bb
We have used the reactivation test (double loop) in a project in the past for tests on weldings of alloy 625 (claddings on mild steel) to detect segregations and phases with lower corrosion resistance. However, it is necessary to develop specific electrolyte compositions for each alloy. We used an electrolyte with 1 M H2SO4 + 1 M HCl + 1 mmol KSCN at 60°C for alloy 625 and were able to demonstrate a deterioration in corrosion resistance when welding energy was too high. The reasons for this were, among others, too high Fe contents, local decrease of Cr and Mo segregation.
Perhaps this will help you with your further research.
Many greetings from Magdeburg,
Andreas
Dear sir, follwing IGC testing may be useful for you.
Streicher Test (ASTM A262 Practice B). Generally used for stainless steel and nickel alloys, the Streicher test involves boiling the specimen in a Ferric Sulfate - Sulfuric Acid solution for 24-120 hours and evaluating the results. The level of corrosion is determined by mass loss.
Dear Dr. Heyn & Dr Raghavaiah, Thanks for the feedback. Much appreciated,
@ Andreas, when adding KSCN, how high do you estimate the risk of also inducing HIC, a hydrogen related corrosion mechanism like HE which also could act on the grain boundaries?
@ Johan, external or internal (residual) tensile stresses are necessary for crack formation. So I see hardly any danger on mechanically unloaded samples. The ad- and absorption of H can of course be favoured by KSCN, but I have not made any investigations on this.
@ Andreas, The main challenge I am always confronted with, is to be able to determine the correct mechanism(s) after failure. That is why I want as 'pure' as possible IGC to observe as sort of reference point/observation.
So thanks for the feedback, I will try out the KSCN based electrolyte and see what degradation mechansims can be obseved following the suggested procedure.
Johan
Follow the ASTM G-28 -02(2015) as Traverso said above. Also consult the book " " Corrosion " by ASM.
Dr. K
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