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  for Metal Finishing since 1989
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Aluminum finish

2000

I am seeking expertise in aluminum plating.

I am currently using an Iridite yellow chromate conversion coating to finish a 15" x 9" aluminum plate (0.100" thick). This part functions as a mounting plate for various sheet metal and plastic components.

The dilemma is that this coating is not robust and is very susceptible to scratches which reveal the aluminum. Consequently, these scratches render the finished good aesthetically displeasing.

The severity of the scratches on this part is very minor. For the most part, the scratches are introduced during handling. For example, packaging paper, if rubbed against the part, is abrasive enough to create unacceptable scratches and marks.

I am seeking a coating that is similar in colour and appearance to the Iridite yellow chromate conversion coating, but more robust. It is also essential that the coating be conductive for grounding purposes.

Any suggestions or references that could point me in the right direction would be sincerely appreciated.

Thank you,

Matthew Kim

ADC Telecommunications

Matthew K [last name deleted for privacy by Editor]
ADC Telecommunications - Minneapolis, Minnesota, USA

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Matthew,

Is there a reason for the chromate/Iridite finish? Does the part need to make electrical contact. If not, there are alternative ways to process those parts that can give you the chromate finish, while giving it a little better abrasion resistance.

Matthew Stiltner
- Toledo, Ohio
2000

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Thanks for your response Matt!

There is no particular reason, per say, for the chromate/Iridite finish. It's one of those cases where the part has always carried this type of finish, and nobody has really questioned it. The finish simply needs to provide basic corrosion resistance as the product is used in an indoor environment.

The finish is required to be conductive per standards in the telecommunications industry.

I am still interested in learning more about an alternative finish, even though it may not be conductive.

Thanks,

Matt Kim

Matthew K [last name deleted for privacy by Editor]
ADC Telecommunication - Minneapolis, Minnesota, USA
2000

Matthew,

I was thinking about this after re-reading your messages. I have a customer that basically goes with your same requirements...chromate as a finished product and can have 0 surface scratches or defects. They eliminated this problem by packaging their materials in plastic baggies similar to a sandwich bag. When you box up a bunch of parts wrapped this way, the potential for scratches is limited because the bags tend to slide against one another. It's not cheap to buy all those baggies is my guess, but it works.

(As far as an "alternative" finish goes, I think you got the e-mail on that, if not let me know and I'll resend it)

Matthew Stiltner
- Toledo, Ohio
2000