Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Etching of Al5083 Aluminum Alloy
Q. I am a P.G. student in India and I am working on Al5083 alloy. I am having problems in getting optical microscopy. I tried different etchants (Kellers, Poultons and Bosserts) and electropolishing (5 ml HBF4 (48%)+200 ml Water) but I am not having success. I would like to know which is the best etchant and step by step procedure for this case? Thank you very much.
Suraya Prakash Raoa research scholar - Chennai, Tamil Nadu, India
2003
A. As you have discovered, Keller's is not the best etchant for revealing grain boundaries in 5xxx alloys, especially those with more than 3% Mg. Barker's and Poulton's, though, should be able to show the general microstructure of 5083. Here are the correct procedures for using them:
Barker's - 5 mL HBF4 (48%) in 200 mL water. Specimen is the anode. Use Al, Pb, or stainless steel as the cathode. Anodize for 40-80 seconds at 0.2 A/cm^2, which is about 20 V dc. The microstructure should be viewed using polarized light. Sensitive tint filters also help.
Poulton's - 50 mL of Poulton's reagent (2 mL HF, 3 mL HCl, 20 mL HNO3, 175 mL water), 50 mL HNO3, 40 mL of solution of 3 g chromic acid per 10 mL water. Use a few drops on the surface for 1-4 minutes. If your sample is not developing well, use the maximum time. Rinse, then swab to remove the smut that develops. Microstructure should be viewed using polarized light, and the sensitive tint will help also.
Another option to consider is Weck's tint etching. It consists of 100 mL water, 4 g KMnO4, & 1 g NaOH. Again, the results are best when viewed using polarized light and sensitive tint filter. Anodizing the surface first may be useful.
Toby PadfieldAutomotive suspension modules - Michigan
2003
Q. Hi my dear colleague;
I am studying on Al5083. and I could not see grain and boundaries. Can you help me? Otherwise I will leave this studying. I got bored studying this. I tried all solution but I could not see.
Please help me.
- Elazig, TURKEY
2005
A. HI DEAR FRIEND
WE HAD YOUR PROBLEM ABOUT AL5083 (ABOUT ETCHANT FOR IT).
WE EXAMINED IT BY NAOH FOR 5-8 MINUTES AND WE COULD SEE METALLOGRAPHY IMAGES OF IT.
BYE
- ALESHTAR-LORESTAN
2007
May 2, 2009
Hi friends.
I solved the problem. Firstly you heat test specimen and later etching. And than you can see grain and boundary.
Bye
- Turkey
A. Hi everybody
About etching 5083, I agree with Toby. You can use Barkers Reagent, Voltage 20V, 0.4 mA, 30-60 sec. If you use polarized light you will definitely see the grains with the clear, colorful and sharp area.
Best Regards
- Iran
May 26, 2011
Q. PLEASE HELP ME IN FINDING THE CORRECT ETCHANT SO THAT IT CAN REVEAL THE GRAIN BOUNDARIES IN THE WELDED PLATE OF AA5052-H32
BARLA MADHAVI- HYDERABAD,ANDHRAPRADESH, INDIA
October 11, 2013
October 2013
Hi Barla. There are some highly informative postings preceding yours. Please try your best to comment on their applicability to your situation, or to explain what you have tried and the difficulties you have encountered, so we can keep this discussion growing. Thanks!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Etching 2014 and 2xxx Aluminum Alloys
Q. I wish to etch 2014 aluminium alloy (90.4 - 95.0 Al, 3.9-5.0 Cu, 0.5-1.2 Si, 0.2-0.8 Mg Fe Mg Mn Ti Zn) to reveal the microstructure. Can anyone recommend a suitable etching solution (and preferably one that does not contain HF)?
Gregory Gibbonsmanufacturing group - COVENTRY, West Midlands, UK
2004
A. I cannot find my reference book, but I find it amazing that your firm would have the mounting and polishing and microscope required for that evaluation and not have a book with solutions for the different things that you might need to be looking for, from grain size to grain boundaries to copper precipitation to ...?
James Watts- Navarre, Florida
2004
A. Other than HF, two etchants that can be used successfully with copper-containing 2xxx series alloys are the following:
25 mL HNO3 (conc) + 75 mL H2O [Immerse at 70 °C for 45-60 seconds]
20 mL H2SO4 (conc) + 80 mL H2O [Immerse at 70 °C for 30 seconds, then rinse in cold H2O]
Toby PadfieldAutomotive module supplier - Michigan
2004
Etching 6061 / SiC
Q. Hi. I have tested number of reagents including Keller's to see the grain boundaries in 6061/ SiC but failed. Please help me with what is best reagent for it.
Imran Khanstudent - Beijing, China
2007
Q. Hello,
My name is Mike. I tried to do etching with Keller's reagent and 0.5% HF. I also tried electrochemical etching with 1.8% Hydroborofluoric acid (fluoboric acid).
Can anyone please help me to etch the aluminum alloy (AA6061-T6)?
Thanks,
student - Sydney, NSW, Australia
2007
Etching Al5456
Q. Hi, I am trying to etch a new variant of Al 5456 (80% Al, 5% Mg, Mn, Cr, Fe,S i).
Kellers is not working, 0.5% HF is not working. Somebody please help me; I am very much worried.
Johny Varghese- Hyderabad, Andrapradesh, India
August 21, 2013
Q. Hello. I have a dissimilar joint of 5083-H12/6061-T6. I tried to etch this very much but I failed. Please tell me how can I do that.
ahmad aziz- tehran, iran
June 3, 2014
A. Hi Ahmad. Maybe a metallographer would understand your question better than I do, but I don't understand what you were trying to do, or what results you got :-(
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2014
Q. Hello. I have a dissimilar joint of 5083-H12/6061-T6. I want to figure out the grain size. How can I etch it?
Thank you
- tehran, iran
June 4, 2014
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Ed. note: Readers may also be interested in these threads:
letter 7041, "Etching Aluminum to Reveal Microstructure"
letter 55644, "Color Etching of Aluminum to Show Orientation of Grains"
A. Try this website where they post a detailed list of common etchants.
http://www.metallographic.com/Technical/Etching.htm#ED
Pacific Automated Welding Solutions - Valencia California USA
February 1, 2018
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