Commonly Used Etchants for Magnesium and Alloys

Composition	Comments
25 mL water 75 mL 3-5 ethylene glycol 1 mL HNO3	Glycol etch, general purpose etch for pure Mg and alloys. Swab specimen seconds for F and T6 temper alloys, 1-2 minutes for T4 and 0 temper alloys.
19 mL water 60 mL ethylene glycol 20 mL acetic acid 1 mL HNO3	Acetic glycol etchant for pure Mg and alloys. Swab specimen 1-3 seconds for F and T6 temper alloys, 10 seconds for T4 and 0 temper alloys. Reveals grain boundaries in solution-treated castings and most wrought alloys.
100 mL ethanol 10 mL water 5 g picric acid	For Mg and alloys. Use fresh. Immerse specimen for 15-30 seconds. Produces grain contrast.