Hastelloy and Haynes alloys

Hastelloy and Haynes alloys

Material Name: Hastelloy and Haynes alloys
Recipe No.: 12060
Primary Chemical Element in Material: Ni
Sample Type: Bulk
Uses: Polishing
Etchant Name: No data
Type (Macro/Micro): Micro
Etching Method: Electrolytic
Etchant (Electrolyte) Composition: 5 gm. oxalic acid mixed with 95 ml HCl (reagent grade)
Procedure (Condition): Electrolytic 6 volts DC, Carbon cathode, Stainless anode probe, 1 to 5 seconds depending on heat treated condition and size of sample
Note:
1. The sample must have a fresh polish. If the surface has been dry, even for a few seconds, give the sample 6 to 10 laps on final .05 micron alumina (Linde "B") cloth then place directly under running water and swab with a cotton pad.
Important Sample surface must be kept wet.
2. Put sample face up in etchant. With good overhead light to visually see sample surface: make contact at end or corner of sample with anode probe, dip carbon cathode into etchant watch to see any surface change – break contact.
3. Important Before removing sample from etchant, agitate to remove any film on surface. Pull sample and put under running water. Rinse with Methanol, then place sample under hair dryer until it is thoroughly dry.
4. If etch is too light and needs to be heavier, do not take sample back to running water and then into etchant. Instead it must go back to the final cloth for 6 to 10 laps making sure that no part of surface dries failure to do this can, and most likely will, result in staining. If the sample does stain do not try to remove stain on final cloth. Rather, go back to the papers at least to the 400 and 600 grit; then 9 micron diamond and then to 0.05 alumina – and again, keeping sample surface wet, repeat as described before.
Reference: Website https://www.haynesintl.com/tech-briefs/general-haynes-international-information/metallographic-preparation-of-hastelloy-and-haynes-alloys-(H-1107), 2019.