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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Hardcoating type 4032 aluminum in black
Q. Is it possible to black hardcoat anodize 4032 aluminum? This alloy contains >10% silicon while MIL-A-8625 / MIL-PRF-8625 [on DLA] warns against attempts to hardcoat any alloy of >8% Si. We have experience with anodizing some castings with 6-8% Si and they can be type II anodized, but the color is not as dark as desired. It also tends to be less uniform both across the surface of the part and from part to part. Are there any specific additives or baths that can be used exclusively for higher Si alloys?
Gordy Seppanenmaterials engineer - Minneapolis, Minnesota
1996
A. Hi, Gordy. One alternative is proprietary technology, consisting of special power supplies, additives, and operating procedures.
These licenses cost thousands of dollars-- and include amp-hour charges as well. It's something you need to think about, not something you buy off the shelf. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1996
A. Sir,
We have a specialty chemistry system here which allows for the safe hardcoating on high copper & silicon alloys.
- Long Island City, New York
1996
A. Luke Engineering has been applying thick (up to 75 um) hardcoating to high silicon/copper aluminum die-castings for over twenty years. The color is naturally a brownish-gray. This hardcoating can be PTFE impregnated or dyed black, however, the color is not as deep or uniform as on normal wrought alloys.
adv.
We have no experience with 4032 alloy but would be glad to hardcoat prototypes for evaluation, free of charge.
Luke Engineering & Mfg. Co. Inc.
Wadsworth, Ohio
1996
A. Metalast has a newer process that has advertised some extremely impressive data, particularly if you do not need a true hardcoat, but one that meets spec and can be two step anodized. I am sure they would like to sell their process or give you a name of one of their licensees. Charlie Grubs is their VP of technology (1996) if you are a follower of light metal processing.
James Watts- Navarre, Florida
1996
Q. Aluminum coating for Aesthetic black requirement and wear resistance for 150,000 cycles (Those many times other part comes and hits Al part)
Amit P- Pune, India
February 1, 2017
A. Hi Amit. More words please! I assume you are looking for this finish? :-)
But are you looking for a shop to do it for you, or looking for the process to do it in house? What alloy are you using please? Thanks.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2017
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