Etching Hastelloy is difficult due to the anti-corrosive nature of these alloys. Hastelloy’s are high temperature corrosion resistant superalloys that are primarily nickel alloys containing various amount of molybdenum, chromium, colbalt, iron, copper, manganese, titanium, zirconium, aluminum, carobon and tungsten.
Sample Preparation: Hastelloy’s must be properly prepared to reveal the true metallographic microstructure. A number of recommended procedures can be found at the following links:
http://www.metallographic.com/Procedures/Super%20Alloys%20Description.htm
http://www.metallographic.com/Brochures/Met-Manual-2b.pdf
CAUTION: Safety is very important when etching. Be sure to wear the appropriate protective clothing and observe all WARNINGS on chemical manufacturersSDS (Safety Data Sheets). Also review COMMENTS Section for each etchant.
| Etchant | Conc. | Conditions | Comments |
| Adlers 300 Hastelloy Etchant Ferric chloride Copper ammonium chloride Hydrochloric acid Distilled water |
45 grans 9 grams 150 ml 75 ml |
Immerse for several seconds. | A very effective etchant for 300 series, austenitic, duplex stainless steels |