57057. Need Tin plating on rare earth magnets (no sub layers)

I have an application that requires excellent adhesion between a permanent magnet substrate (NdFeB) and a tin overlayer. The tin should have a minimum thickness of 15um and cannot be applied to the magnet with a prep layer. (Must be tin directly to magnet). In application, the magnets are exposed to high stresses, so the plating cannot delaminate.

The magnet itself measures approximately 2" x 1.5" x .5". We have sample magnets to test our process but would like to start with smaller sizes to establish the process due to the high costs of rare earths today.

Quantities upwards of 50k pieces annually are possible, but in all likelihood hoover around 20k pieces.