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Galvanic action of brass/bronze plated aluminum

2003

We are considering brass/bronze plating a round 6063-T6 aluminum extrusion in order to improve the OD bearing characteristics.
During use, the extrusion OD is clamped along it's length, top and bottom, by martensitic steel cantilever spring fingers that provide a detent as well as a prevailing torque during rotation of the extrusion within the springs.

There are seven 12mm wide fingers (they alternate between top and bottom with four on top and three on the bottom) that exert a total clamping load of 700N on the extrusion. The fingers are flat giving a line contact between the fingers and the extrusion.
The spring has no coatings or finishing. The extrusion OD is currently shot blasted, hard coated and then greased before the spring is assembled onto it.
This process works moderately well but has a rough sound and feel initially.

We are looking to improve the product feel and sound as well as eliminate some steps in the extrusion manufacturing process.
I am concerned about galvanic action between the aluminum and brass and the ability of the plating to stand up to the rubbing and compressive loads generated by the spring.

Any thoughts?

Russ Holdredge
product development - Zeeland, Michigan

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If you do not require conductivity, then look into Hard Anodising instead of the Brass/ Bronze. I also do not foresee any galvanic corrosion issues cropping up with the bronze.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2003

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