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Gold/nickel plating on A356 CastAluminum

I am an engineer in the telecommunications industry. We make radios (approx 1.5 ft X 1.5 ft X 1.5 ft) that are mounted outside on building tops and towers anywhere in the world. The housings for the radio are cast aluminum (Alodined) boxes sealed with an environmental rope gasket (not hermetically sealed, but keeps water out in swimming pool). Inside the radio, there are some rf components mounted to the housing (Alodined aluminum surface). One of the rf components has substrates and feed thru pins that touch the surfaces of rf component.The housing is made from the Alsic process. My question is, what plating standards (nickel and gold) and thicknesses should I use for the Alsic (A356) housing such that I will avoid corrosion, but provide for good conductivity/solderability? The corrosion requirement for the radio (outside the radio) is 30 day salt fog test per ASTM 117.

Gregory L. Procopio
- Orlando, Florida, USA
2000

My suggestion is not to use gold on a porous Aluminum surface. The pores will not plate over and you will have localized high potential galvanic cells even with a nickel plate between the parts.

Chuck Smith
- McKinney, Texas
2002