COMMON ETCHANTS
CAUTION:Safety is very important when etching. Be sure to wear the appropriate protective clothing and observe all WARNINGS on chemical manufacuters MSDS. Also review the COMMENTS and CONDITIONS Section for each etchant.
Recommended Etchants
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The following table lists the most commonly used etchants
Etchant |
Composition |
Conc. |
Conditions |
Comments |
ASTM No. 30 |
Ammonia |
62.5 ml |
Mix Ammonia and water before adding peroxide. Must be used fresh. Swab 5-45 seconds |
For etching copper, copper alloys and copper-silver alloys. |
Kalling's No. 2 |
CuCl2 |
5 grams |
Immersion or swabbing etch at 20 degrees Celcius |
For etching duplex and 400 series stainless steels and Ni-Cu alloys and superalloys. |
Carpenters Stainless Steel Etch |
FeCl3 |
8.5 grams |
Immersion etching at 20 degrees Celcius |
For etching duplex and 300 series stainless steels. |
Kellers Etch |
Distilled water |
190 ml |
10-30 second immersion. Use only fresh etchant |
Excellent for aluminum and titanium alloys. |
Klemm's Reagent |
Sodium thiosulfate |
250 ml Saturated |
Etch for a few seconds to minutes | For etching alpha-beta brass, bonze, tin, cast iron phosphides, ferrite, martensite, retained austenite, zinc and steel temper embrittlement. |
Kroll’s Reagent |
Distilled water |
92 ml |
Swab specimen up to 20 seconds |
Excellent for titanium and alloys. |
Nital |
Ethanol |
100 ml |
Immersion up to a few minutes. |
Most common etchant for Fe, carbon and alloys steels and cast iron - Immerse sample up from seconds to minutes; Mn-Fe, MnNi, Mn-Cu, Mn-Co alloys. |
Marble's Reagent |
CuSO4 |
10 grams |
Immerse or swab for |
For etching Ni, Ni-Cu and Ni-Fe alloys and superalloys. Add a few drops of H2SO4 to increase activity. |
Murakami's |
K3Fe(CN)6 |
10 grams |
Pre-mix KOH and water before adding |
Cr and alloys (use fresh and immerse); iron and steels reveals carbides; Mo and alloys uses fresh and immerse; Ni-Cu alloys for alpha phases use at 75 Celcius; W and alloys use fresh and immerse; WC-Co and complex sintered carbides. |
Picral |
Ethanol |
100 ml |
Seconds to minutes |
Recommended for microstructures containing ferrite, carbide, pearlite, martensite and bainite. Also useful for magnetic alloys, cast iron, high alloy stainless steels and magnesium. |
Vilella’s Reagent |
Picric Acid |
1 gram |
Seconds to minutes |
Good for ferrite-carbide structures (tempered martensite) in iron and steel |