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Electroless nickel (EN) suffers non-conductivity

       

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We had some aluminum shelves electroless nickel plated. They came back with a yellow hue and were non-conductive. Any ideas?

Truman G. Glasscock
- Huntsville, Alabama

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First of two simultaneous responses -- +++

Does your electroless nickel plater also do anodizing?

Todd Osmolski Charlotte Plating, Inc. Charlotte, North Carolina, USA

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Second of two simultaneous responses -- +++

Probably, an adhesion bake at an excessively high temperature oxidized the surface. Adhesion bake on aluminum should be at 375 F for non-heat-treatable alloys, or 250 F for heat-treatable alloys (Mil-C-26074 [link is to spec at TechStreet]E, Classes 3 & 4, respectively). A straw colored tarnish suggests a hardening bake > 600 F, as performed on steel (Class 2).

Ken Vlach - Goleta, California

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The symptoms you describe indicate that the aluminum was not electroless nickel plated but rather it s anodized and dyed gold. Come back with more information. Electroless Nickel freshly plated, especially only after a few days WILL conduct. Anodizing is insulative.

Robert H Probert Robert H Probert Technical Services Garner, North Carolina Editor's note:        Mr. Probert is the    author of Aluminum How-To / Aluminio El Como