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Ultrasonic cleaning after electroless plating on aluminum
Q. We make a part for the dental industry. The part is machined 6061 aluminum; the plating specification is noted here:
plate per AMS2404 Class 4
- Hi-phos electroless nickel .0007-.0009" thick.
- Bake at 375° F. ± 15 degrees for 1 - 1.5 hours".
I need to provide a cleaning solution to remove biomatter that is similar to current practice. Typical cleaning process is to ultrasonic clean, rinse with water, then autoclave.
a couple of parts have come back with some pitting and blistering. What is causing the plating to lift off the alluminum? Is it the cleaning solution or the act of ultrasonic cleaning? I have always thought it was the cleaning solution until someone said they use tap water. Now I don't know. Thanks in advance. Brian
- Santa Barbara
June 25, 2012
A. 7 tenths EN will still have a few pores in it. I consider it to take 1.5 thou to be pore free.
Your cleaning chemical is probably quite alkaline. The ultrasonics will pump alkaline material into and out of the pores. This WILL react with the aluminum.
Find a less aggressive cleaning material and ultrasonic it for only as long as it takes to get it clean and then ultrasonic it in distilled water to purge any chemical still in the pores. Use a separate unit for this if possible and change the water with each use.
- Navarre, Florida
June 29, 2012
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