Plating on Aluminum
Chrome Plating and Electroplating Aluminum
Aluminum castings, extrusions, forgings, and machined billet can all be decorative nickel chrome electroplated to improve the appearance and enhance the corrosion performance.
Each of these combinations requires a slightly different activation sequence to optimize the electroplating bond adhesion. As a rule, to achieve a perfect nickel-chrome finish on an aluminum casting, a “copper buff” step needs to be done.
After the initial polish and buff, the aluminum casting is electroplated with a heavy deposit of copper. After copper plating, the parts are then buffed again to further smooth out the surface. The final step is to activate the copper surface and electroplate with nickel chromium.
Aluminum metal quickly forms an oxide which can weaken the plating adhesion. To prevent the oxide from forming, we use a zinc immersion film called a zincate prior to the nickel strike.
For difficult to plate alloys we use the zincate step twice called “double zincate” for optimal adhesion.
Decorative nickel chrome plating on aluminum alloys has been a reliable commercial process since the late 1960’s when improvements were made in the zincate process.
Common applications of nickel chrome on aluminum include:
- Automotive fuel doors
- Step tubes
- Motorcycle valve covers
- Primary covers
- Brake & clutch levers
- Master cylinder components
Electroless nickel can also be plated directly onto aluminum using the zincate process as an intermediate step. Electroless nickel can provide increased wear and corrosion protection.
Applications for plating electroless nickel on aluminum include:
- Memory disks