Letter 16098

Coating for aluminium  

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We are looking for a coating on aluminium connector bodies (6082) which will withstand 500 hrs minimum salt fog test, can be applied with precise thickness - especially on threads, and where adhesion is guaranteed. The coating should be jet black (other colour possibilities very useful) Maximum depth of 30 micron. Lubricity would be an advantage, however Teflon/nickel on the mating parts covers this.

Pat Crossan
Engineering and Design - Cork, Ireland

With careful preparation of aluminum for plating, a high phosphorus electroless nickel 25 microns followed by a mid phosphorus electroless nciekl deposit containing sulphur. Sulphur compounds are often used as stabilizers in mid phos electroless nickel solutions. Followed by a short dip, 30 to 40 seconds, in 1:1 nitric acid until a black color apears. The black is a result of etching leaving sharp holes and dendrites that absorb light creating the black color. The black will not wipe off.

Don Baudrand Don Baudrand, Consultant   Poulsbo, Washington

Pat,

You can have EN blackened. It's not uncommon and fits every aspect of your search (except just two colors, natural and black).

Bye,

Guillermo Marrufo
Monterrey, NL, Mexico

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