Etching gold 1

[EngineerDave]

We have a strange request to etch a gold structure. The gentleman claimed he had a company use an etchant that contained cyanide. I don't have this in house and don't plan on ordering it. Is there any quality alternative you can recommend?

 

[nbucska]

You may try to use potassiumferricyanide, it may work, too.
I know it dissolves Ag -- I don't know about speed...


<nbucska@pcperipherals.com>

 

[unclesyd]

The first on is the one I've used. This is essentially Aqua-Regia tones down. The etchant is really nitrosyl chloride. Do this in a hood or outside and stay up wind.
I threw in the cyanide one just for you.


Material: Gold (Au), platinum (Pt), palladium (Pd)
Type: Macroetching
Method: Chemical etching
Etchant (electrolyte): 66 ml hydrochloric acid, 34 ml nitric acid.
Procedure: Few minutes. Use hot and fresh!.
Remarks: Au, Pt alloys and Pd alloys.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 43.

Material: Pure gold (Au), palladium (Pd) and rhodium (Rh)
Type: Microetching
Method: Chemical etching
Etchant (electrolyte): 40 (1) ml nitric acid, 60 (10) ml hydrochloric acid.
Procedure: Few seconds to 1 min. May require heating. Use only fresh!.
Remarks: Pure Au and Pd. Au-Pd, Pd alloys with more than 90 % concentration of precious metals. Rh alloys.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p.44.

Material: Palladium (Pd), gold (Au) and platinum (Pt)
Type: MicroetchingMethod: Chemical etching
Etchant (electrolyte): 100 ml distilled water, 10 g potassium cyanide.
Procedure: 30 s to 2 min.
Remarks: Au alloys with less thn 90 % content of precious metals.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

Material: Palladium (Pd), gold (Au) and platinum (Pt)
Type:: Microetching
Method: Chemical etching
Etchant (electrolyte): 100 ml distilled water, 10 g ammonium persulfate.
Procedure: 30 s to 2 min.
Remarks: For Au alloys with high content of precious metals. White gold. Pd and Pt alloys.
Reference: G.Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

Material: Gold (Au), palladium (Pd), platinum (Pt)
Type: Microetching
Method: Chemical etching
Etchant (electrolyte): 30 (50) ml distilled water, 25 (100) ml hydrochloric acid, 5 (10) ml nitric acid.
Procedure: 1-5 min. Use hot.!. Remove precipitate of gold chloride with ammonia water.
Remarks: Pure Pt and Pd. Au alloys. Proportions in parentheses especially useful for Pt.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

Material: Gold (Au), palladium (Pd), platinum (Pt)
Type: Microetching
Method: Chemical etching
Etchant (electrolyte): 100 ml hydrochloric acid, 1-5 g chromium (VI) oxide.
Procedure: Seconds to minutes.
Remarks: Pure Au and Au-rich alloys. Pd and Pd alloys.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

Material: Gold (Au), palladium (Pd), platinum (Pt)
Type: Microetching
Method: Chemical etching
Etchant (electrolyte): 30 (50) ml distilled water, 25 (100) ml hydrochloric acid, 5 (10) ml nitric acid.
Procedure: 1-5 min. Use hot.!. Remove precipitate of gold chloride with ammonia water.
Remarks: Pure Pt and Pd. Au alloys. Proportions in parentheses especially useful for Pt.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

Material: Gold (Au), palladium (Pd), platinum (Pt)
Type: Microetching
Method: Chemical etching
Etchant (electrolyte): 100 ml hydrochloric acid, 1-5 g chromium (VI) oxide.
Procedure: Seconds to minutes.
Remarks: Pure Au and Au-rich alloys. Pd and Pd alloys.Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.


Material: Platinum (Pt), gold (Au)
Type: Microetching
Method: Electrolytic etching
Etchant (electrolyte): 100 ml distilled water, 5 g potassium cyanide.
Procedure: 1- 2 min, 1-5 V ac, 0.5-1.5 A/cm2, Pt cathode.
Remarks: Pt and Pt alloys, Au and Au alloys.
Reference: G. Petzow, Metallographic Etching, ASM (American Society for Metals), 1978, p. 45.

 

[EngineerDave]

Thanks Unclesyd. You gave me some options. I will try them now.


Yeah I can't make any of the ones that stink too bad. I made that mistake last Wed (HCL and H202). I had it in the fume hood, but didn't have the exhaust on. Big mistake. All I can say is the last half hour of work in the lab was cancelled!